I like to read a good book or anything interesting online (I'm slightly addicted to reddit and wikipedia), listen to music, or if the weather's nice, just go for a hike in the woods or something else outside.
I usually take the time to work out 3 or 4 times a week if I can help it.
Depending on my surroundings I can be quiet and reserved, or pretty ridiculous... I'd like to think that I know when each is appropriate. I get along well with most people, and I have a pretty good sense of humor. I know a little bit about a lot of things, so I'm usually good for conversation, whatever the topic.