@jwitherspoon2009,
- Exercise (biggest one for me)
- Do something that has "flow" -- instant feedback (especially if what is stressing me out is some big project that's taking a long time). Computer games are good for this, but a small, easily achievable project also works (making chocolate chip cookies, say).
- Spend time with friends and family (especially a long, no-agenda lunch with a friend)
- Clean
- Do something mindless (like watch TV or read a stupid but entertaining book)