It's Always Sunny in Philadelphia (2005)

Frank's Brother - S7-E5

Other mistake: In the opening of this episode the screen reads "3:50pm On a Wednesday." When Gino (Frank's Brother) is reading the letters meant for Shadynasty, he says "Meet me at the airport, Friday, at 5:00, Terminal C." The gang and Gina then go along to the airport that very afternoon - a Wednesday - to try and meet Shadynasty and get her and Frank back together. And of course she is there, despite it being a Wednesday, not a Friday.

Frank Reynolds: We gotta definitely write a song about how we do not diddle kids! "Do not diddle kids, it's no good diddling kids."
Mac: There is no quicker way for people to think that you are diddling kids than by writing a song about it.

Who Pooped the Bed? - S4-E7

Trivia: According to the show's assistant prop manager, there were around 100 "poos" created for this episodes, many of which were made from different materials, including a food thickening agent, sheetrock mud and a cookie dough mixture.

TedStixon

Bums: Making a Mess All Over the City - S3-E14

Question: Does the junkyard cat actually belong to one of the actors or is that a whole different deal?

fukawa