Not Every Set Visit Is "Sunny"

We find out if it really is Always Sunny in Philadelphia as we go on set for a 4th season shoot of the hit FX show. Glenn Howerton "Dennis Reynolds," "Rob McElhenney "Mac," Charlie Day "Charlie," Kaitlin Olson "Dee Reynolds," and Danny DeVito "Frank Reynolds" are all on hand to show us a sneak peek into the 4th season where the cast puts on a musical about Day Man. Hosted by Jill Wilderman.