Well someone said this:
To find out how many calories the Wii game Just Dance burns, I wore a calorie counting mechanism called the Body Bugg, and played thirty nonstop minutes of the dancing game. I am in my twenties, female, 5’8 and 133 pounds.
In half an hour I burned a whopping 190 calories playing Wii Just Dance 2 (which should be very similar to the first version in terms of caloric burn).
To break that down, that is roughly:
6 calories a minute
96 calories in 15 minutes
190 calories in 30 minutes
380 calories in 1 hour
570 calories in 1½ hours
760 calories in 2 hours
If you are heavier than 130 lbs and/or male, your caloric burn while playing Just Dance will be even higher.
Hypothetically speaking, 1 ½ hours of Wii Just Dance every day of the week would help you to lose 1.15 pounds each week, without any other changes to your diet or activity levels (see equation below).
Again, if you are heavier than 130 pounds, male, or have high muscle content, the number of calories Wii Just Dance burns and your weight loss potential will be even higher.