Here's a primer to get ready for the Sweet 16:
1. The favorites
Nothing has changed from the first weekend to the second, except that Pitt is gone from the top line. The Panthers may have been the third No. 1 seed, but they were always the most vulnerable of the four. The favorites to win the national championship remain the same as they were on Selection Sunday: Ohio State, Kansas and Duke.
The Buckeyes are the No. 1 overall seed and have done little to change that billing through the first three rounds of the NCAA tournament. Ohio State still has the best low-post scorer in the field in freshman Jared Sullinger and the most prolific group of 3-point shooters. And the Buckeyes had the most dominant performance of any of the top teams heading into the Sweet 16 by absolutely crushing George Mason.
Kansas pulled away from Illinois in the second half Sunday night, and while the Jayhawks may not have as many stars outside of the Morris twins, they still have an experienced group that has handled plenty of curveballs throughout the season. And outside of Duke's Mike Krzyzewski, Bill Self may be the coach best-suited to deal with a changing roster throughout the course of the season.
Duke got a real scare from Michigan, escaping by two points in Charlotte after Darius Morris couldn't convert a runner in the middle of the lane. But the Blue Devils now have star freshman guard Kyrie Irving healthy and running as a playmaking mate to Nolan Smith, forming the toughest backcourt tandem in the field. Irving and Smith can both change the game in a flurry and will make the Blue Devils tough to stamp out this weekend. It's hard to remember another No. 1 seed/Final Four favorite picking up a top-three draft pick just for the NCAA tournament after missing most of the season.
2. Stars on display
Jimmer Fredette, BYU: Fredette is a threat to score as soon as he crosses midcourt. One of three favorites to win national player of year, he's morphed into a one-name celebrity and has been a headline attraction from the moment the season started. While Jimmer is no Sting, Bono, Madonna or Prince, he's become a first-name celebrity in his own right. He's mentioned by his first name so often, some might question whether he has dropped his last name altogether to assume rock-star status.
Kemba Walker, Connecticut: Fredette has been the long-range bomber and led the nation in scoring during the regular season. But Walker has been the player with the flair for the dramatic. He has won games in Maui; Austin, Texas; Storrs, Conn.; and, of course, in New York City on the game's most impressive stage. If Jimmer can carry the Cougars to Houston, then so too can Kemba for the Huskies.
Derrick Williams, Arizona: Williams blocked shots to beat Washington in the Pac-10 regular season and Memphis in the NCAA second round and converted a three-point play to beat Texas on Sunday. Williams is as efficient as any player in college basketball and in competition to become a top-three draft pick if he chooses to leave Arizona after the season.
Jared Sullinger, Ohio State: Sullinger is a throwback, a traditional low-post college player who loves to do the dirty work, get someone on his back, spin and score. He is an anchor for the Buckeyes who can bail them out of any treacherous possessions.
Kyrie Irving and Nolan Smith, Duke: Irving could be the top pick in the draft, while Smith may end up being a lottery selection. Both can deliver the spectacular play and make the game-changing/winning shot.
Brandon Knight, Kentucky: John Calipari has coached plenty of star point guards, from Derrick Rose to Tyreke Evans to John Wall. He has another star that has matured into a leader in Knight. If the Wildcats need a bucket or a play to be made, Knight can deliver.
Marcus and Markieff Morris, Kansas: Marcus gets the headlines, but Markieff is fully capable of stealing them, as this twin combo is a more productive version of the Collins and Lopez twins of recent stock from Stanford. If Kansas wins the national title, it will be because of these two.
Kawhi Leonard, San Diego State: He's not a household name, but he should be since he is extremely productive in the post, doesn't mind doing the little things and will end up playing for years in the NBA.
Matt Howard and Shelvin Mack, Butler: Howard is a winner. He will make plays, get knocked in the face and keep coming back and still find a way to score or board. Mack is as a good a guard as there is remaining in the field. It's hard to doubt this pair's ability to win in the NCAA tournament.
Jordan Taylor, Wisconsin: If you saw Taylor's performance against Ohio State in Madison, Wis., earlier this season, you know how he can take over a game. He has plenty of Vinnie Johnson in his game and can be the microwave to heat the Badgers up during a cold spell quickly.
Harrison Barnes, North Carolina: Barnes put up 40 on Clemson in the ACC tournament. He is a calm, cool cat who never seems rattled anymore. He can score inside, hit 3s and can score in bunches. He is a rising star, but surely you already knew that.
Kevin Anderson, Richmond: Anderson was the best player not named Tu Holloway in the A-10 this season. (Teammate Justin Harper also has a solid argument.) Anderson can get his own shot and has proved himself to be quite a leader for the Spiders the past two seasons. He will likely be in the NBA next season.
3. Coaches in demand
Shaka Smart, VCU: The Virginia Commonwealth coaching pipeline from the Colonial to high-major programs should continue with Smart's run to the Sweet 16 and possibly beyond. Anthony Grant and Jeff Capel landed in the SEC and Big 12 respectively after stints at VCU (although Capel just got fired at Oklahoma). Smart is next in line. He will likely be a candidate to replace Bruce Pearl at Tennessee, assuming that move is made soon, and will likely be a candidate at NC State once it gets through trying to romance a star coach who won't move. If Mike Anderson were to move from Missouri to Arkansas, Smart could be in play in Columbia, too.
Chris Mooney, Richmond: Richmond athletic director Jim Miller is already gathering names as possible replacements in case Mooney moves. There is already interest from Georgia Tech, and Mooney could be a player at Tennessee and possibly at Mizzou, too. He has done a marvelous job at Richmond and could be on that list at NC State as well as in play at Oklahoma if the Sooners don't get their top choice.
Buzz Williams, Marquette: The Golden Eagles don't consider themselves a steppingstone job, and if that's the case they had better lock up Buzz. He is now a hot commodity in the Southwest, with Oklahoma a natural fit and Arkansas a real threat if the Hogs don't go with Anderson. Arkansas is also interested in Texas A&M's Mark Turgeon, and if somehow that domino were to fall, then Buzz fits in College Station, too. Williams will have no shortage of suitors with Marquette's surprising Sweet 16 run.
Dave Rose, BYU: Don't be fooled into thinking that Brigham Young coaches can't move just because they haven't historically gone on to big-time jobs from Provo, Utah. Rose loves BYU and has an emotional tie to the Cougars after his near-death experience with cancer last year. But Rose should at least get some inquiries from other schools thanks to the job he has done at BYU. If schools like Oklahoma, Arkansas, Georgia Tech, NC State (and Missouri if it were open) were smart, they would consider Rose. His style of play is entertaining to watch, he can recruit, he has high character and has done one of the best coaching jobs in the country.
4. Conferences on the rise
The Mountain West: BYU is out the door after this season, heading to the WCC as its football-driven move to independence forced the Cougars to look for a new home. But the MWC can relish the fact that it finally put multiple teams in the Sweet 16 with BYU and San Diego State. Even with BYU's departure, the league can sell its success well in the offseason, and there is no reason to believe SDSU, UNLV and New Mexico are heading for a drop-off.
The Colonial Athletic Association: The CAA is now the hot league outside the power six and MWC. The A-10 still has its share of top teams (Xavier, Richmond and Temple), but the CAA is one to watch. The Colonial was deep this season with its most competitive league ever. Three teams made the field; now one is in the Sweet 16. Jobs in the CAA have become more attractive, as Ron Hunter left IUPUI for Georgia State to be in the league. Even last-place Towson is suddenly an intriguing destination.
5. Welcome back
Florida: The Gators won consecutive national championships in 2006 and '07 but the recruiting class that followed, led by Chandler Parsons and Alex Tyus couldn't handle the weight or responsibility of the expectations that followed that success. Finally, they got the right pieces around them, were unselfish in their approach, matured and won the SEC regular-season title and advanced to the Sweet 16. This group can now have its own legacy in Gainesville, Fla., something Parsons and Tyus said was a must in the preseason. Getting back to the Sweet 16 is a sign that the Gators have returned to the national stage after a three-year hiatus.
6. The next Butler
The candidates are Butler, BYU, San Diego State and VCU. Butler and BYU have the best shot at getting to the Final Four out of the Southeast Region in New Orleans. Even if VCU gets past Florida State, it would likely have to face Kansas. San Diego State has a rough road ahead with Connecticut and possibly Duke in its path to Houston. Butler and BYU could face each other in the Elite Eight. Losing Gordon Hayward seemed to be an easy way to dismiss the Bulldogs' chances of making another Final Four run. This crew has proved it had more than just a great team last year; it has a great program.
7. The toughest ticket
Newark, N.J.: Three of the four teams in Newark have some of the most loyal fan bases remaining in the field. Kentucky fans will flock to New Jersey to see the Wildcats, just like they would to Maui or pretty much anywhere on the planet. North Carolina has always been a big attraction in the New York area. Ohio State fans love their football first and foremost but will travel for a favorite in hoops. Marquette has its loyal crew, too. It will be a hard ticket to get.
8. The wide-open region
The Southeast: Even if Pitt was still in the field, the answer would not have changed, but now it's more pronounced. You could make an argument for any of the four teams to win in New Orleans: No. 2 Florida, No. 3 BYU, No. 4 Wisconsin or No. 8 Butler, but none should be favored over the other. Whoever emerges from this group to get to Houston likely won't be favored to win the title, but shouldn't be discounted.
9. The biggest home-court advantage
Arizona and San Diego State are the de facto home teams in Anaheim, Calif. Maybe playing close to home doesn't matter as much -- Washington and Michigan were both one bucket away from taking North Carolina and Duke into overtime in Charlotte -- but Arizona fans should outnumber Duke in one regional semifinal and Connecticut will be grossly overmatched in fan support by San Diego State, which is just two hours away from Orange County.
10. A surprising discovery
Butler and Wisconsin may have as many NBA draft picks as any other team left in the field outside of North Carolina, Duke, Ohio State, Kentucky and Kansas. Butler and Wisconsin didn't get to the Sweet 16 solely because each team plays hard, defends, runs solid offensive sets and has experienced players. Watching the players, talking to NBA personnel and comparing who is currently still playing in the NBA, it's clear to see that Butler's Howard and Mack are legit NBA role players, as are Wisconsin's Taylor and Jon Leuer. No one said they're all-stars, but these four players will earn quality paychecks at the next level.
11. Handled adversity
Kansas had the most emotional trauma to deal with this season, as Thomas Robinson endured the loss of three family members, including his mother. Issues of eligibility, suspensions and injuries also befell key players, yet Kansas still won the Big 12 regular-season and tournament titles and earned a No. 1 seed.
BYU lost its top rebounder and interior player in Brandon Davies after he was suspended for the remainder of the season for an honor code violation, yet still earned a Sweet 16 berth with a convincing win over Gonzaga.
Connecticut coach Jim Calhoun was tagged by the NCAA's committee on infractions for failing "to promote an atmosphere of compliance," receiving a three-game Big East suspension for 2012. The Huskies entered the Big East tournament as a No. 9 seed yet still won five games in five days to win the league championship.
Florida State had to endure a late-season injury to its best player, Chris Singleton, yet reached the Sweet 16 with a win over Notre Dame. FSU may have had the toughest conference tournament loss too, losing to Virginia Tech in the ACC quarterfinals when Derwin Kitchen's game-winner came just after the buzzer sounded.
12. A second chance
The selection committee clearly thought long and hard about putting VCU and Marquette in the field and might not have placed Richmond in the field had the Spiders not won the A-10 tournament. VCU and Marquette were No. 11 seeds as at-large teams; Richmond was a 12 as an automatic qualifier. All three made the most of the opportunity by proving they belonged with Sweet 16 runs.
13. Championship pedigree
Getting to the Sweet 16 is not a fluke. Just look at the championship experience of some of the coaches remaining in the field: Duke's Mike Krzyzewski has won four NCAA titles, North Carolina's Roy Williams, Connecticut's Jim Calhoun and Florida's Billy Donovan have won two each. Kansas' Bill Self and San Diego State's Steve Fisher have each won one. And Ohio State's Thad Matta, Kentucky's John Calipari and Butler's Brad Stevens have all coached in the national title game.
14. Preseason prognostication
The picks in October weren't so far off after all. Duke, Ohio State, North Carolina, Kentucky, San Diego State, Wisconsin, BYU, Kansas, Butler, Richmond and Florida were all either picked in the preseason to win their respective conferences, to be top-25 teams or to at least compete for their league titles. Whether they were consistently good all season, matured at the right time or simply got on a roll late in the season, here they are in the Sweet 16. Conversely, Connecticut, Arizona, Marquette, VCU and Florida State have already far exceeded expectations with their Sweet 16 appearances.
15. Hoop hotbeds
OK, who had two teams from the state of Florida (the Gators and Seminoles) in the Sweet 16 in the preseason? The best guess is no one. Who had two teams from the city of Richmond, Va., in the Sweet 16 in October, let alone on March 13? Those chances were even more remote, but the Rams and Spiders are in, making Richmond the epicenter of hoops for the next four days.
16. Rematches or possible matches
Florida plays BYU in the Sweet 16 after the Cougars beat the Gators in a first-round overtime thriller last season. That's the one certain rematch, but there could be some other tantalizing ones in the Elite Eight or Final Four. Duke could face Connecticut (they played in the 1999 title game and 2004 Final Four); Duke could play Butler (it's not a total reach) for the national championship for the second year in a row; the Blue Devils could meet North Carolina again in the national semifinal; Ohio State could meet Florida in a rematch of the 2007 national championship game; Kentucky could play Duke in the national semifinal, matching the two programs that played one of the best tourney games ever in the 1992 Elite Eight. And the dream matchup of the two most exciting players remaining in the field is still alive in a possible national championship game: Kemba versus Jimmer.
Andy Katz is a senior writer at ESPN.com.