Texas A&M (A&M strands for "Agriculture and Military") has the tradition of the 12th man. In 1922, the website explains, A&M was playing Centre College and was digging deep into its reserves. Coach Dana Bible remembered a former football player, E. King Gill, who was helping out in the press box during the game, and asked him to come to the sidelines and suit up to be the team's last reserve. At the end of the game (which the Aggies won), Gill was the last untapped reserve and was dubbed the "12th Man." Now, the 12th man honors each and every student that attends A&M football games, students that stand during the entire game, ready to be called to duty should the need arise. A sign adorns the stands at Kyle Field: "Home of the 12th Man."

A player on the kickoff team, wearing number 12, represents the entire student body on the football field. Surely, this is one of college football's greatest traditions.
In 1990, A&M officials got the phrase "12th man" trademarked. But those dirty rascals, the Seattle Seahawks officials and fans, began using that phrase to refer to the home crowd at Seahawks games. A&M officials sued for trademark infringement. The case was recently settled out of court.
The Texas school sued the Seahawks earlier this year, prior to the Seahawks' Super Bowl appearance. A&M used the phrase for years and received a trademark for the slogan in 1990.
In a statement, the Seahawks said that the lawsuit has been dismissed, and that the team and the Texas school reached a settlement. The Seahawks did not disclose details.
"Texas A&M University and the Seattle Seahawks announced that they have agreed on the scope of Seattle's future use of the 12th Man trademark. The agreement resolves all of the issues presented in the pending lawsuit, which has been dismissed. Neither side admitted any fault or liability. The Seahawks acknowledge Texas A&M's ownership rights in the mark and will continue to use the mark under license in connection with the Seahawks' operations, promotions and fan activities in the Pacific Northwest," Seahawks officials said in a statement.
Here's the Wikipedia entry on 12th man.
Chris Rangel has some other thoughts including:
Will A&M go after Stanford Men's basketball "6th Man" merchandising?
Readers: should A&M have been granted this trademark in the first place given that it's a commonly-used phrase and given that officials and fans of other teams, including the Seahawks, used the phrase before it was trademarked? Is this really something that should be treated as intellectual property?
Update: PowerReader Brad corrects me: the M in A&M stands for Mechanical, not Military. I stand corrected.