Mad Men Season 5 Episode 4 (04/15/12)
Pete is miserable. He is taking driving classes, and has his eye on a young lady in the course. Trudy throws a dinner party where Don fixes the sink, and everyone finds out about Ken Cosgrove's writing habits.
After Lane's attempts to secure Jaguar fall through, Roger, Pete, and Don take the man out for the night. He wants to party, so Roger brings them to a whore house. Everyone gets a girl except Don.
The Jaguar guy's wife finds out what happened, which pulls the plug on the whole thing. Lane finds out and wants to have it out with Pete. The two men fight, and Pete is the one who hits the floor.