Like other have said above, it's a bit of a no-brainer that a lot of my spare time is spent surfing/messing around with Pokecharms, hanging out in a few choice mIRC channels, or using MSN. Other than that... I shall list in no particular order. Bandwagon
1. I have a number of websites I visit on a regular basis, so each time I jump online I tend to surf through them one after another. This can take anywhere from 2 minutes to a couple of hours depending on site updates.
2. Similar to Alex, I spend a good portion of my free time zoning out to various DVDs series' or downloaded Anime. At any given time there's always something I'm watching through, whether it be a new series or one of my past favourites. Part of it is just to unwind and relax, but one major factor that initiates my TV time are meals. After living away from home and having a busy roommate it became habit to watch something while I ate - eating alone without some sort of distraction bores me to tears.
3. Like a good portion of people here, I'm a gamer. I've been a one nearly all my life, so playing video games in my spare time has always been a constant (the only varying factor being how long/frequently I'd play each week). At the moment, I tend to split my time between my Wii, 360, and DS, but occasionally dip into my PC and PSP collections. Would also be playing my PS2 as well if the thing wasn't still borked...
4. I love creative writing, so when an idea strikes me and I've got the time/means to do something with it I tend to spend several hours writing various fictional pieces/stories. Even if I'm bored/unfocused I'll often grab a pad of paper or open up a text window/program at random and start mindlessly writing things down just to empty my thoughts. I'm always thinking about some random story idea and incorporating life experiences into it, even if the piece stays locked eternally in my mind.
5. I too enjoy hanging out with friends and family. Family tends to wear me out after awhile, but friends are always a blast to hang with - even if all we're doing is talking. I'll talk on the phone with my best friends for hours if allowed to. We just lose track of time, lol.
6. Going for walks while zoning out to music is another thing I adore. It's like my perfect drug. I doubt there's single other factor in life that can put me at total peace as easily as this can. I've pondered deeply as to why it affects my mind the way it does, but I think most of it is simply the action of letting my mind relax/be absorbed by the music while walking and taking in the environment around me. Staring up at the sky, or off into the horizon... I'm an outdoors person at heart (love being surrounded by trees or near a body of water), and the element of music twisting my thoughts/emotions (because I let it do so) just takes things to new level entirely.
7. I daydream, a lot, and I enjoy it more than I can say. Sometimes I feel like my life is one big daydream, really, just because of how my mind works. As a runner-up to walking/music for putting my mind at peace, daydreaming would probably be it. Sometimes I find if I can't get time to myself to just sit/lie back and think I start going a bit insane, lol. I'm a "smell the roses" type of person and NEED my downtime to function, and this is probably the main reason why.
Err... I think that's mostly it beyond other random stuff like reading, playing with my dog, stargazing, etc. I love stargazing as much as taking walks, but I haven't had the chance to do much of it lately.