Here's a list of ballparks my wife and I have been to for at least one game:

American League	National League
Angel Stadium: Los Angeles Angels Camden Yards: Baltimore Orioles Comerica Park: Detroit Tigers Fenway Park: Boston Red Sox Jacobs Field: Cleveland Indians McAfee Coliseum: Oakland A's Metrodome: Minnesota Twins Rogers Centre: Toronto Blue Jays Safeco Field: Seattle Mariners U.S. Cellular Field: Chicago White Sox Yankee Stadium: New York Yankees	AT&T Park: San Francisco Giants Dodger Stadium: Los Angeles Dodgers Miller Park: Milwaukee Brewers Olympic Stadium: Montreal Expos Petco Park: San Diego Padres PNC Park: Pittsburgh Pirates Shea Stadium: New York Mets Wrigley Field: Chicago Cubs Veterans Stadium: Philadelphia Phillies

Miscellaneous Stadiums, Arenas, and Coliseums where we've seen at least one game:

Rose Bowl Stadium January 1, 1998: Washington State University v. University of Michigan
Martin Stadium: Washington State University
Friel Court at Beasley Coliseum: Washington State University
Philips Arena: Atlanta Hawks
TD Garden: Boston Bruins
HP Pavilion: San Jose Sharks
Midway Stadium: St. Paul Saints
Frontier Field: Rochester Red Wings
Blue Cross Arena: Rochester Americans
War Memorial Arena: Syracuse Crunch
Ohio Expo Center Coliseum: Columbus Chill
Spokane Arena: Spokane Chiefs & Seattle Sonics (Pre-season)