Go ahead, play the Wii! It's better than sitting around.

Participating in the actual sport is more optimal but you can burn calories playing the Wii. In a 30 minute session you can burn 216 calories playing Wii boxing, 159 calories playing Wii Tennis. If you want to get the best workout that you can while playing the Wii then you need to mimic the real movements as closely as possible. So say "yes" next time one of your children or grand-children ask you to play!