It's Always Sunny in Philadelphia (2005)

S18E8 Mac and Dennis Tear Their ACLs

Following a disastrous Christmas card mishap, Charlie tends to Mac and Dennis, who are both stuck in bed, while trying to figure out which of them is the true mastermind behind all their schemes. Meanwhile, Dee and Frank, fed up with always being the last to know anything, resolve to turn the tables on the group's communication hierarchy.