It's a self-perpetuating wave of partying, and alumni nostalgia for the drunken revelry when they were students, amplified by the schools to draw even more crowds -- therefore more ticket, parking and concession sales, advertising revenues from television, and (most important of all) alumni donations.

The good colleges spread that revenue around -- the bad ones keep all the money in their athletic departments, completing the feedback loop. Guess which category Penn State falls into...

Looking at it another way (as a former marching band geek): Football? What's that? It's Halftime Season!