Here are, in no particular order (other than Ohio Stadium being the best football environment I've ever been in), are the football stadiums I've seen games in over the years:
College
Ohio Stadium (OSU) - many games
Nippert Stadium (UC) - a handful of games
Yager Stadium (Miami) - Miami vs. Bowling Green
Perry Stadium (BG) - many games
Michigan Stadium (Michigan) - Michigan vs. OSU twice and Mich. vs. ND
Notre Dame Stadium (ND) - Notre Dame vs. Purdue
Commonwealth Stadium (UK) - Kentucky vs. Tennessee
Memorial Stadium (Illinois) - Illinois vs. OSU
Spartan Stadium (Michigan State) - MSU vs. OSU
Neyland Stadium (Tennessee) - Tennessee vs. UC a couple of weeks ago
Folsom Field (Colorado) - games vs. Texas Tech and West Virginia
War Memorial Stadium (Wyoming) - Cowboys vs. Bowling Green
Memorial Stadium (Indiana Univ.) - Indiana vs. OSU
Rose Bowl - 1997 OSU vs. Arizona State
Sugar Bowl (Louisiana Superdome) - 1998 OSU vs. Florida State
NFL
Paul Brown Stadium (Cincinnati) - numerous games
Heinz Field (Pittsburgh) - Bengals vs. Steelers in 2003 (Bengals won; Steelers fans were awful)
Cleveland Municipal Stadium (Browns) - Bengals vs. Browns in final game in old stadium; still have part of the seat I walked out of the stadium with