‘It’s Always Sunny in Philadelphia’ Fourth Season Ends Tonight

Season Four of FX’s It’s Always Sunny in Philadelphia comes to an end at 10pm EST tonight with another typically wacky episode, this one called “Nightman Cometh.”

It’s all about Charlie, who, with the rest of the gang’s help, puts on a musical production based on his song named “Nightman.”

Get an advance peek at the super-cheesy rock opera in the three preview clips after the jump, two featuring a most eye-catching costume worn by Dennis.

It’s Always Sunny in Philadelphia airs Thursdays on FX at 10pm EST.