Charlie Day, Kaitlin Olson, Rob McElhenney and Glenn Howerton kicked off their long-running and record-breaking sitcom on FX on Aug. 4, 2005 with "The Gang Gets Racist." Here's looking back at some of the gang's worst moments and It's Always Sunny's standout episodes. ALSO: Watch the making of the homemade It's Always Sunny pilot.
TOPICS: It's Always Sunny in Philadelphia, FX, FXX, Charlie Day, Danny DeVito, Glenn Howerton, Kaitlin Olson, Rob McElhenney