"It's Drinkin' Time!":
I haven't been on a college campus tour in a long time, but here's a pretty good prank courtesy of the Dartmouth Jack-O-Lantern. (The prank begins after about 45 seconds.)
Prospective students turned off by that during the tour probably didn't want to go to Dartmouth anyway. Hat tip: The IvyGate Blog

  UPDATE: In the comment thread, "Q the Enchanter" writes, "Isn't this an indictment of our entire American society?" Dean Wormer, is that you?