I loved Artie dancing (though the end was harsh!). Also, the shout-out to a karaoke bar staple was priceless (and I LOVED the shout-out to Dr. Horrible--it was subtle, but it was there--"in the laugh"), but the true winner. . .
Especially this (pretty sure this was B's favorite moment):
Oh, and the Gaga episode next week? Can. Not. Wait.