1. Get outside. It doesn't have to be fancy - walk the dog, weeding, shoot baskets, go to the beach, go on a bike ride, etc.
2. Watch a great old movie - like How to Marry a Millionaire or Some Like it Hot.
3. Work on a project - if you can only concentrate on something easy, work on somethingeasy. But working on figuring sometheing out means you're not whatever else is on your mind and you're getting some amount of control over whatever you're working on.
4. Find something funny. When someone makes me laugh or smile, I forget that I'm busy being upset.
5. Talk it over with someone.
6. Baby chortles, knock-knock jokes told by a novice, etc.
7. Go on an adventure.
8. Read a good book. Perhaps not good in the sense of high brow literature. But good in the sense of engaging, uplifting, fun.
9. Catch up with what your peeps are up to - Facebook, blogs, twitter, etc.
10. Surfing ravelry or flickr for new projects.