If I know I'm not going back out for the night, I usually shower (if I feel like I produced any sweat, haha) than read or chit-chat.
If I'm just burning a pinch of time and I'm worn out from walking around and spending my whole paycheck, then there's a lot of random chit-chatting, reading, or nerf gun wars. XD Oh my goodness, that was so much fun last year.
EDIT: After reading more posts in this thread, I feel so pathetic for actually spending any time in the room like me and my friends tend to do. This year it'll probably be much less though since I have a new camera and hope to get a lot of great clips this year.
Next con is pending....
(Wow what a bad SN. I made it up several years ago and thought it sounded cool. |D Oops.)