re: What is the biggest non Auburn game you have been to?

1991 World Series Game 4. Braves beat the Twins 3-2 when Mark Lemke scored on a sac fly in the bottom of the ninth for the win.

Honorable mentions:
Hideo Nomo throwing a no-hitter at Camden.
First ever Washington Nationals game in DC.
Strasburg's pro debut in DC.

I haven't seen too many great basketball games or non-Auburn football games.