1. Go as something sweet. (Photo by twelves/Flickr)
2. Be fancy by taking a 5-star meal to go. (Photo by twelves/Flickr)
3. Make a statement. (Photo by twelves/Flickr)
4. Going as your favorite movie character is never risky business. (Photo by KGO-TV)
5. Get in the Waldo spirit and challenge your friends to find you! (Photo by KGO-TV)
6. Dress as your favorite crustacean...no one will be crabby about that! (Photo by piyush.k/Flickr)
7. Recreate your favorite childhood computer game, like the Oregon Trail. (Photo by twelves/Flickr)
8. Or Tetris! (Photo by KGO-TV)
9. Or be old school and go as your favorite board game! (Photo by twelves/Flickr)
10. Show your love for San Francisco by dressing as your favorite landmark. (Photo by piyush.k/Flickr)
11. Or street. (Photo by keved/Flickr)
12. Or when all else fails...be a taco! (Photo by keved/Flickr)