Banging your head against a wall burns 150 calories per hour.

150 calories certainly isn’t very much, and banging one’s head against the wall for an hour would probably result in at least a concussion, but considering everything we do costs energy, it kind of makes sense.

Here's some other weird ways of burning calories:

• Chewing gum
• Raking leaves
• Eating spicy food
• Breathing through your nose
• Taking a cold shower
• Doing a cannonball
• Giving your dog a bath
• Licking a stamp

(Source)