David Copperfield Slipped Me a Roofie
Two and a Half Men Season 6 Episode 14 (02/02/09)
The episode opens with Alan and Melissa (Kelly Stables) having breakfast when Melissa pulls Charlie aside to tell him she wants to throw Alan a surprise birthday party. On his birthday, Melissa takes Charlie to a restaurant where his mother, Charlie, Berta, Melissa's mother (Carol Kane) and Jake surprise him there. After the dinner, everyone goes around giving a "toast" to Alan where all they do is rip into him.
After being humiliated by everyone, Melissa asks Alan to move with her and her mother and they leave the restaurant. Alan comes home to collect his things to move in, but leaves behind Jake at Charlie's. Melissa and her mother attempt to make Alan as comfortable as possible. When Melissa goes out to the grocery store to buy food to cook for Alan, Melissa's mother gives Alan some of her special banana bread (made with weed). After eating the bread, Alan and her mother end up in bed together and Melissa walks in on them!
The episode ends with Alan coming back home and Charlie definitely glad to have him back. Jake didn't even notice he was gone.