Refers to the crappy team many Division FBS (I-A) colleges use as a warm-up for their football season and to sell tickets to alumni. Teams that fill up on cupcake teams often get fat and lazy, resulting in a thorough ass-whooping come time for conference games.
Every now and then the cupcake wins, prompting a torrent of lulz on every NCAA internet forum. See Appalachian State vs. Michigan.
Vanderbilt is the SEC cupcake team.