Jack Corson, aka "Mad Jack," raises the Cardinals' flag -- a new one -- wide and high at every home game.
Each week he's in charge of creating a huge banner, 11 feet by 14 feet, which has a game-specific message.
Corson, 50, from Chandler, Ariz., software project manager, recalls Cardinals games by the banner's message -- for one memorable win that kept the Vikings out of the playoffs a few years ago, it was "Forget the No. 1 pick -- play the spoiler." That they did.
His proudest moment came when he hoisted the banner honoring former Cardinals safety Pat Tillman, who was killed in action in Afghanistan by friendly fire in 2004. The team was playing the Patriots, and the message read, "Corporal Pat Tillman, a true patriot."
"It's become a tradition," Corson said. So has his hard-core rooting.
He's been cheering on the Cardinals since he became a season-ticket holder in 1993, courtesy of a gift from his wife.
"She rues the day she did that," he joked.
One of his best team memories was a home win over the Chargers in 1998 that sent the team into the playoffs -- fans carried the goal posts from the stadium. The team went on to beat the Cowboys for its only playoff victory since the franchise has been in Arizona.
San Francisco 49ers
Jan Boehm's Sunnyvale, Calif., house runs on solar energy, but it's a passion for the 49ers that powers the 74-year-old fan.
Boehm first got a charge out of the Niners while watching them bully the Broncos in Super Bowl XXIV.
"It was an unbelievably jaw-dropping experience," said Boehm, who has been known as "Niner Jan" ever since.
Boehm gets to Candlestick Park on occasion these days, but prefers to watch her team from her home, which appears dedicated to the Red and Gold.
She proudly displays more than 1,000 items of 49ers memorabilia, including pictures of her all-time favorite players, Steve Young and Brent Jones.
Boehm is undaunted by San Francisco's recent struggles.
"A true fan," she said, "stands by his or her team whether it's winning or losing games."
Now retired from the semiconductor industry of Silicon Valley, Boehm lives less than a 15-minute drive from the 49ers headquarters and the road is a two-way street.
The Bay Bombers keep her running so she does what she can to reciprocate, regularly dropping off care packages for the players that include fresh-baked cookies.
It's a sweet obsession, for Boehm and her Niners.
"I really enjoy making it fun for everyone else."
From that statement you might gather Josh MacLachlan is not your typical crazy football fan. And you'd be right.
Sure, he loves his Seattle team and sports a Seahawks-hued peace sign on his face, which goes nicely with his long hair.
But the 39-year-old construction consultant from Bellingham, Wash., mainly loves to make the games entertaining for others.
MacLachlan has season tickets at Qwest Field with seven others, but he also keeps two extra seats for those who haven't been to games before or maybe didn't have a good experience at a previous outing.
"We are not the crazy guys who go in full Seahawks gear, but we do high-five every person in our section after the game and people know who we are," MacLachlan said.
MacLachlan lived in the San Francisco Bay Area as a youth and, though he hates to admit it, grew up a 49ers fan. But his father lived in Washington, and when the Seahawks came about in 1976, he became a fan and has stayed one ever since.
"I expect to go to the Super Bowl every year," he said. "I think really all fans think that of their team."
MacLachlan is quick to mention he's quite the devoted family man. He and his long-standing partner Martha Rikard have a son, Griffon, now 3, who was but a tot when the family traveled to Detroit for the Seahawks' first Super Bowl in 2006.
Rikard says MacLachlan is too modest to agree, but he's the greatest Seahawks fan she knows.
She said they leave late after every home game because he positions himself at the bottom of Section 301 and slaps fives with "everyone" who comes down the stairs.
and Brett Pauly
St. Louis Rams
Tom Whelan Jr.
For superfan Tom Whelan Jr., five words sum up why he cheers for what he clearly feels is the best team in the NFL.
"The Greatest Show on Turf," Whelan said, recalling the nickname of the Rams offense during its 1999-2001 hot streak.
"The run that they had when they were at their peak was just really impressive to watch as they tore teams apart that came here to play them," he said. "It was the most prolific offense in the history of the NFL. Not only that, but they have the greatest helmets in league history."
Whelan, 47, of St. Louis, is a high school social studies teacher.
He also sells fireworks on the side and creates his own oohs and aahs by driving his Ramsmobile around town.
Spray-painted in the Rams colors, his 1975 Dodge Journey, described by Whelan as a "box on wheels that shouldn't even be on the road," has a furry, blue ceiling and is adorned with team memorabilia from dashboard to rear bumper.
Whelan takes his tailgating seriously, too, showing up at home games, early, really early -- between midnight and 2 a.m. And more than once he has dared to enter the sea of red at Arrowhead Stadium in Kansas City wearing his blue and gold.
A Cardinals fan back in the day, he adopted the Rams in 1995 when they arrived from Los Angeles. During St. Louis' big run in 1999, Whelan said, he set the tone for the entire high school by wearing a Rams jersey during the magical ride that ended with a victory in Super Bowl XXXIV.
"When Ricky Proehl made that catch," said Whelan of the NFC championship-clinching touchdown that season, "I was overwhelmed. Finally, St. Louis was headed to the Super Bowl."