This one took me years to hunt down, since it didn't even make SMU's Top 90 most memorable football moments, so you can see how unimportant it was. Apparently, practically nobody affiliated with Southern Methodist University cares about remembering it, but for some reason I do.
In 1976, SMU was 2-8 coming into their final game against 5-2-1 Arkansas. It was the last game for SMU's little wishbone quarterback Ricky Wesson, 5'9" and 163 pounds, who had started for the last three and half seasons. He wasn't much of a passer. These days he couldn't play quarterback anywhere except the military academies, but in those days there was a wide variety of offensive strategies in college football, and so there was room here and there for "good man in a foxhole" type undersized gamers.
In his finale against Arkansas, however, Wesson had the passing game of his life, throwing four touchdown passes (as well as rushing for 80 yards) to put SMU up 35-31.
Still, with a minute left, Arkansas was driving down the field past the overmatched SMU defense for a seemingly inevitable come-from-behind win. So, quarterback Wesson begged his coach Ron Meyer to put him in on defense at free safety. He made the interception in the end zone to save the game.