If you want to burn some extra calories this Thanksgiving, but you reeeally don't want to get out of your chair lest it is stolen by a 10-year old, perhaps you should consider Sudoku.

The popular logic puzzle has been shown to burn up to 90 calories an hour, according to "mental-agility experts" who want you to log on to their Web site. Ahem.

Still, the British Dietetic Association has said that making your brain work hard will cause it to use more calories. Thinking all day, however, won't cause you to lose weight, since the brain can't burn fat molecules, only sugar. But if you have a tendency towards little snacks, it could keep those from turning into fat.

Also, if it takes you an hour to do a Sudoku puzzle, you could probably use the practice -- a little logical-reasoning skills never hurt anyone.

In case you need a way to burn off the cheese ball you ate before guzzling all the gravy in the house without going to the gym, check out one of our favorite math puzzles.