Tim Tebow won't be the first NFL training camp sideshow: Five more, from Brock Lesnar to a Hall of Famer

The Jacksonville Jaguars signed Tim Tebow, and everyone lost their dadgum minds.

It seemed outrageously unacceptable that the Jaguars would devote a training camp roster spot to a 33-year-old who hasn't played football in six years and is attempting to transition from quarterback to tight end. It wasn't hard to feel cynicism toward the Jaguars and Tebow, especially when his jersey quickly jetted to the top of the NFL's sales list.

There is, however, another way to view the training camp sideshow coming to Jacksonville later this summer, one that is decidedly less angry and more in line with NFL history. As it turns out, lots of NFL teams have used summer roster spots for less-than-super-serious purposes. The others just came at a time when there was less scrutiny on every personnel move.

Some of those experiments worked out; most of them did not. But all of them have provided lasting wrinkles in the story of pro football. What follows are a handful of notable examples, all reminders that football is supposed to be fun and that some teams don't take the 90th roster spot as seriously as you.

2004: Brock Lesnar in Minnesota Vikings camp

No one laughed when Lesnar started telling people that he wanted to try pro football. At 26, he was eight years removed from his last high school game. But he had rare physical traits as a 286-pound professional wrestling champion who ran the 40-yard dash in 4.7 seconds and had a 35-inch vertical leap. He also benched 475 pounds, squatted 695 pounds and had delivered a convincing mean streak via his WWE character.

The Vikings were a natural landing spot, given his history as an All-American wrestler at the University of Minnesota. Coach Mike Tice was hoping to spice up camp, if nothing else, and owner Red McCombs knew a winning sideshow when he saw one.

Wearing No. 69, Lesnar appeared in preseason games as a defensive tackle and a cover man on kickoffs. His most notable moment, though, was getting involved in a series of fights with Kansas City Chiefs offensive linemen during a joint practice. At one point, Lesnar ripped the helmet off a Chiefs player and, after being sent to the sidelines, stirred nearby fans into a frenzy.

Ultimately, the learning curve proved too steep. Lesnar went back to wrestling and kept pushing for new areas to dominate. He found one a few years later and won the undisputed heavyweight championship in the UFC.

1963: George Plimpton in Detroit Lions camp

Plimpton, 36 at the time, was a writer who helped pioneer immersive sports journalism. In other words, he figured that a good way to report on something was to participate in it. So he started pitching NFL teams on a training camp invite as a "last-string quarterback" to give him material for a book. Plimpton found a taker in the Lions, who hadn't been to the playoffs in five seasons and wouldn't go back for eight more.

The book was called "Paper Lion," in which Plimpton demonstrated the wide gap between amateur and professional athletes. Coaches and team executives were aware of the bit, but Plimpton asked them not to tell players because, he wrote, "I'd like to be thought of as just another rookie."

Wearing No. 0, Plimpton got a handful of snaps in an intrasquad scrimmage -- the offense moved backward on each play -- and had hoped to play in a preseason game before commissioner Pete Rozelle barred it, according to later reports. But the experience was rich enough to spawn a book that led to a movie starring actor Alan Alda, who received a Golden Globe Award nomination for his performance. The Lions went on to a 5-8-1 record, missing the playoffs, but their issues went far deeper than a pretend backup quarterback.

Five decades later, Plimpton's book spawned a similar project. Author Stefan Fatsis persuaded the Denver Broncos to let him kick in their 2008 camp and later published a book titled "A Few Seconds of Panic."

1982: Renaldo Nehemiah in San Francisco 49ers camp

NFL teams had been pursuing track stars for decades by the time Nehemiah entered the scene. But Nehemiah, who had set a world record in 110-meter hurdles the year before, generated a frenzy among NFL squads when he expressed a desire to play in the NFL. Washington figured it had the inside track on signing him, given Nehemiah's time as a University of Maryland student, but the 49ers swooped in with the first contract guarantees in franchise history to secure him as a training camp receiver.

In reality, those guarantees ensured that Nehemiah would make the team -- even though it had been five years since he played football. Given his speed, it made sense to put him on the field if for no other reason than to stretch defenses.

Like his track/football predecessors, he struggled with drops. For a time, his name was synonymous with the idea that elite speed can't paper over inexperience with the game itself. But the real turning point in his career, he later told Sports Illustrated, came when he was knocked unconscious by a hit in 1983.

In 40 games over three seasons, Nehemiah caught 43 passes for 357 yards and four touchdowns.

1969: Jimmy "Oops" Hines in Miami Dolphins camp

A gold medalist at the 1968 Olympics, Hines was the first man to break 10 seconds in the 100-meter dash. That was more than intriguing for NFL teams, who had also pursued fellow 1968 star Tommie Smith and would later do the same for John Carlos. The Dolphins, who were in their third year of existence and had a combined 7-21 record in their previous two seasons, drafted Hines in 1968. Based on his 100 time, Hines qualified as the fastest player in the history of the NFL at that point.

But he had never played football before, and let's just say Hines earned his nickname during training camp. After assigning him the No. 99, the Dolphins found out that he couldn't catch the ball with any consistency. They didn't give up on him, however. After all, you can teach people to catch, but you can't teach speed. Or so they thought.

Hines spent the 1968 season on a taxi squad. He made it onto the field for nine games in 1969 for the Dolphins and one for the Chiefs in 1970. He finished his NFL career with two receptions for 23 yards, one 7-yard carry and a 22-yard kickoff return.

1965: "Bullet" Bob Hayes in Dallas Cowboys camp

Some of these unorthodox experiments have actually worked. To be fair, Hayes had more football experience than most of the other track stars whom NFL teams later tried to convert. He had been recruited to play football at Florida A&M, where he also developed into an Olympic-level sprinter.

The Cowboys and Denver Broncos both used future draft picks to secure his rights in 1964, after which he went to the Olympics and won two gold medals. He joined the Cowboys in the summer of 1965. No one knew what to expect, but his impact was immediate: Hayes' speed was the talk of camp.

"It was like he was melting, he was so fast," fellow receiver Frank Clarke reportedly said.

He could catch, too. Defenders couldn't stay with him, and they lost ground on even the shortest routes. Hayes led the league in touchdown receptions in both 1965 and 1966. His speed changed the game, requiring defensive coaches to sharpen zone defenses and sparking an intense scouting search for speed from any source.

Hayes was inducted into the Pro Football Hall of Fame in 2009, having finished his career with a telling average of 20 yards per reception.