I've been to the following in my life time so far:
MLB
Oriole Park at Camden Yards (Orioles, of course)
Citizens Bank Park (Phillies)
Nationals Park (Nationals, of course)
PNC Park (Pirates)
Minor League Baseball
Ripken Stadium (Ironbirds)
NFL
M&T Bank Stadium (Ravens)
Lincoln Financial Field (Eagles)
Memorial Stadium (Ravens first ever home game)
NCAA Football
SECU Stadium (Maryland)
Navy–Marine Corps Memorial Stadium (Navy)
I wished I didn't go so late into the seeing other Stadiums thing.
MLB
Oriole Park at Camden Yards (Orioles, of course)
Citizens Bank Park (Phillies)
Nationals Park (Nationals, of course)
PNC Park (Pirates)
Minor League Baseball
Ripken Stadium (Ironbirds)
NFL
M&T Bank Stadium (Ravens)
Lincoln Financial Field (Eagles)
Memorial Stadium (Ravens first ever home game)
NCAA Football
SECU Stadium (Maryland)
Navy–Marine Corps Memorial Stadium (Navy)
I wished I didn't go so late into the seeing other Stadiums thing.