Sex burns like 900-1000 calories per hour, and well it's lots of fun...
Okay now seriously, when I want a really good, yet fun workout and I'm bored with the whole running thing, I put on my headphones, turn the music up loud, close the curtains and dance. You don't have to be any good, you just have to move for a whole song, and then another and another. Sometimes I clean the house at the same time and other times I'll do the same move for a whole song. Believe me if you twist side to side for the 3:45 minutes that it takes to listen to the Twist, your sides will feel it tomorrow. And guess what? Music is relaxing and just might help your blood pressure a little too.