It's confirmed, playing video games burns calories (so does breathing!)

[Thorin]

http://news.bbc.co.uk/1/hi/health/6376637.stm

Games consoles such as Nintendo Wii require players to use body movements to control the action.  A study by Liverpool John Moores University found regular use could help shift 27lb (12.25kg) a year.

There's no link to the data, though, and the test pool was tiny

The study measured the impact on five girls and seven boys, aged between 13 and 15, of playing both an active and inactive console.  During 15 minutes of play using a traditional joypad operated console, energy expenditure increased above resting values by an average 60%.  In comparison, when using the Wii console, the participants' energy expenditure increased 156% above resting.  Based on the average gaming week of 12.2 hours, this translates to a potential 1,830 calories burned per week when using Wii - 40% more than when using a traditional format console.

Now I wonder whether these kids actually stood up to play the games, or if they were playing something like Legend of Zelda: Twilight Princess?  Because really, the amount of activity you do when playing Wii games has a lot to do with the Wii interface...  Heck, even playing Tennis from Wii Sports can be done laying down with a cover over you and the controller under the cover (although I'm sure it would look *terribly* bad if your wife walks in).