I just joined so I figured I would add all the stadiums I've been to over the years.

American League
Chicago:
Comiskey Park I and II It's my home park, so too many times to name.
Toronto, ON:
Rogers Centre 2007.
New York, NY:
Yankee Stadium I 2008, Yankee Stadium II 2012.
Minneapolis, MN:
HHH Metrodome 2004, 2009.
Cleveland, OH:
Progressive Field 2008.
Kansas City, MO:
Kaufman Stadium 2007.
Oakland, CA:
Oakland-Alameda County Coliseum 2009.
Detroit, MI
Comerica Park 2011.

National League
Chicago:
Wrigley Field 1985, 1987.
Milwaukee, WI:
Miller Park 2004, 2005, 2006, 2007, 2009, 2012.
St. Louis, MO:
Busch Stadium III 2007.
Cincinnati, OH:
Great American Ballpark 2007.
New York, NY:
Citi Field 2012.
Pittsburgh, PA:
PNC Park 2008.
San Francisco, CA
AT&T Park 2009.

Triple A
International League
Buffalo, NY:
Buffalo Bisons NorthAmericare Park 1999, Dunn Tire Park 2004, Coca-Cola Field 2010. (Same stadium, just different names.)
Indianapolis, IN:
Indianapolis Indians Victory Field 2005, 2012.
Louisville, KY:
Louisville Bats Louisville Slugger Field 2005, 2007.
Toledo, OH:
Toledo Mudhens Fifth Third Field 2005, 2010.
Rochester, NY:
Rochester Red Wings Frontier Field 2006, 2011.
Columbus, OH:
Columbus Clippers Cooper Stadium 2005 (game was rained out), 2008, Huntington Park 2012.
Syracuse, NY
Syracuse Chiefs Alliance Bank Stadium 2011.

Pacific Coast League
Omaha, NE:
Omaha Royals Johnny Rosenblatt Stadium 2007.
Oklahoma City, OK:
Oklahoma Redhawks AT&T Brocktown Ballpark 2007.
Memphis, TN:
Memphis Redbirds AutoZone Park 2007, 2008.
Des Moines, IA:
Iowa Cubs Principal Park 2008.
Sacramento, CA:
Sacramento River Cats Raley Field 2009.
Fresno, CA:
Fresno Grizzlies Chukchansi Park 2009.

Double A
Eastern League
Binghamton, NY:
Binghamton Mets NYSEG Stadium 2006, 2011.
Akron, OH:
Akron Aeros Canal Park 2008.
Erie, PA:
Erie SeaWolves, Jerry Uht Park 2005, 2006, 2008.

Texas League
Wichita, KS:
Wichita Wranglers Lawrence-Dumont Stadium 2007.
Tulsa, OK:
Tulsa Drillers Drillers Stadium 2007.

Single A
California League
San Jose, CA
San Jose Giants San Jose Municipal Stadium 2009.
Modesto, CA
Modesto Nuts John Thurman Field 2009.
Visalia, CA
Visalia Rawhide Recreation Park 2009.
Stockton, CA
Stockton Ports Banner Island Ballpark 2009.

Single A
Midwest League
Dayton, OH:
Dayton Dragons Fifth Third Field 2005, 2008.
Geneva, IL:
Kane County Cougars Philip B. Elfstrom Stadium 2006, 2007, 2009, 2010, 2012.
Clinton, IA:
Clinton Lumberkings Alliant Energy Field 2007.
Davenport, IA:
Swing of the Quad Cities John O'Donnell Stadium (now called Modern Woodman Park) 2007.
Cedar Rapids, IA:
Ceder Rapids Kernels Veterans Memorial Park 2007.
South Bend, IN:
South Bend Silver Hawks Stanley Coveleski Regional Stadium 2007.
Appleton, WI:
Wisconsin TimberRattlers Time Warner Cable Field 2007.
Beloit, WI:
Beloit Snappers Harry C. Pohlman Field 2006, 2007.
Comstock Park, MI:
West Michigan Whitecaps , Fifth Third Ballpark 2007, 2008, 2011.
Midland, MI:
Great Lakes Loons Dow Diamond 2007, 2008, 2011.
Lansing, MI:
Lansing Lugnuts Oldsmobile Park 2007, 2008.
Ft. Wayne, IN:
Ft. Wayne Wizards Memorial Stadium 2008.
Ft. Wayne TinCaps Parkview Field 2010.
Burlington, IA
Burlington Bees Community Field 2009.
Peoria, IL
Peoria Chiefs O'Brien Field 2009.
East Lake, OH:
Lake County Captains Classic Park 2008, 2010.
Bowling Green, KY:
Bowling Green Hot Rods Bowling Green Ballpark 2012.

South Atlantic League
Lexington, KY:
Lexington Legends Whitaker Bank Ball Park 2012.
Charleston, WV:
West Virginia Power Appalachian Power Park 2012.

Single A Short Season
New York-Penn League
Jamestown, NY:
Jamestown Jammers Russell Diethrick Park 2010.
Batavia, NY:
Batavia Muckdogs Dwyer Stadium 2010.
Niles, OH:
Mahoning Valley Scrappers Eastwood Field 2010.
Burlington, VT:
Vermont Lake Monsters Centennial Field 2011.
Troy, NY:
Tri-City Valley Cats Joseph L. Bruno Stadium 2011.
Fishkill, NY:
Hudson Valley Renegades Dutchess Stadium 2011.
Auburn, NY:
Auburn Doubledays Falcon Park II 2011.
New York, NY:
Staten Island Yankees Richmond County Bank Ballpark at St. George 2012.
Brooklyn Cyclones MCU Park 2012.

Unaffiliated Minor League
Joliet, IL:
Joliet Jackhammers (Northern League), Silver Cross Field 2004, 2009.
Gary, IN:
Gary Southshore Railcats (Northern League), U.S. Steel Yard 2008.
Schaumburg, IL:
Schaumburg Flyers (Northern League) Alexian Field 2009.
The Northern League no longer exists. Nor do the Schaumburg Flyers. The Joliet Jackhammers are now known by a different name.