--spoiler--
leonard: [going to see his room] is this it?
sheldon: no, this is my room. people don't go in my room.
leonard: so where do you sleep?
sheldon: I don't understand.
leonard: well, if people don't go in there and you are people, aren't you? [sheldon still looking confused] i'm making a joke.
sheldon: do you do this often?
leonard: on occasion.
--spoiler--
