Didn't Know About It's Always Sunny in Philadelphia

There's only one reason to compare the largely amoral bar keepers that populate FXX's It's Always Sunny in Philadelphia with the serene '50s vibe of The Adventures of Ozzie and Harriet: With its 13th season premiering on September 5 and a 14th season already ordered, It's Always Sunny will soon tie Ozzie as the longest-running live-action comedy sitcom in the history of television.
Before that milestone, the gang of Paddy's Pub still has a 13th season to get through without succumbing to the effects of sniffing gasoline. Check out some facts on the show's history, its alternate-universe Dee, and how the production almost killed national treasure Danny DeVito.