If you go to this site:
And enter in your weight, it will tell you how many calories you burn off doing different exercises. It's very helpful.
According to the site, if you weight 120lbs, and walked 2mph briskly (not carrying anything), you would burn 54 calories per hour.
Playing basketball, for example, burns 86 calories per hour (if you weigh 120lbs).
hope this helps!