I get deeply involved in studying. I can get lost in Wikipedia. I browse a site called Everything2 which is as addictive as Wikipedia, except that there's both factual and creative content. Sometimes I find the best unpublished short stories. Someone who goes by "thecustodian" keeps an immense active list of recommended books, so I'll randomly sift through those. I go to eclectic blogs like Blue Tea when I want to see what's new and interesting on the Internet: short surrealist games, industrial photography, biotech news; or the guy who poured 80,000 litres of copper sulfate solution into an abandoned apartment building and covered every visible surface in glittering blue crystal.
This kind of stuff cheers me up, gives me some sort of connection to the real world, and lets me zone out when that's all I can do.
When I need distraction or focus, I listen to music. When I want the world to disappear or when I've stopped feeling real, I listen to music compulsively. I make playlists that converge on a theme.
I used to run marathons until I injured my knee permanently, but I still go hiking. Sometimes I ignore the pain and go back to running. There's nothing like the high after running twelve miles.
When everything starts to suck and there's nothing I can realistically do, I switch tracks and take risks I wouldn't have otherwise. I force myself to meet new people from very different walks of life and actually go somewhere together, try something new. I take up new hobbies that require physical and mental focus. I'm into metalworking and branding. I fantasize about the new activities I'd take up if I had a limitless income.
I spend too much time outdoors.