Usually skim through the posts, which are informative, entertaining and hilarious; don't always reply though, unless something really grabs me.
What do you do when waiting for your turn?

When waiting for my turn, I try to have a life outside chess, but it doesn't really work out well...
I look at my games and plan possible moves. I also try to figure out what my opponents might be planning. Chess is similar to football. Defense is as important as offense. I also look at the forums. Sometimes I also enter questions in the chat box next to the chess board and find out information about my opponents and share information about myself.

I like to give comments like these and try to solve problems which is nothing but multi-tasking!!!!!!!!!!!

I catch up with forums,tryied Live chess but keep getting disconnected,so I watch the odd film or check out some decent music if not I grab a pint of Guinness and scratch the owl head,lol!

I just go to another game, comment o a friends page, send an email, work on homework, listen to music, get up and walk around, and just do anything. xD I think you all get the idea now. I cannot help but be hyper and keep myself preoccupied with doing different things at once.

I go to other internet forums and web sites in search for new interesting stuff there.
(Yeah, I know that's heresy).

Start doing what I should be doing other than playing chess... studying. I use chess as a reward system, "I've studied for 5 min I can play a few games" chess + last semester in college + general education classes = NO MOTIVATION!!!

Pick my guitar and strum away Eagles' Tequila sunrise, Seven Bridges Road, and then Take It Easy...'then the paul simon hits...Sound of Silence, The Boxer...walllla!!!

Read books, solve endgame studies, solve tactics (in tactic trainer or a book), chess mantor, analyze my games, play and analyze live chess, chill here at the forums, read articles, read blogs, watch vids. Probably forgot something.
Me, i look for more seeks.