There are so many funny things here, it's hard to itemize them. Start with Raj and Howard doing "filk" music. The song they write is hilarious but really weird. If that's Howard playing, he's very good (he sang in a previous episode. Penny talks Leonard into moving out of Sheldon's apartment, leading to incredibly funny stuff, including Sheldon returning to twelve years previously (in his own head). Then there is the ongoing Stuart saga.
Review of The 2003 Approximation
