May sound strange but being a gamer helped me find a fun cardio work out. It is called Dance Dance revolution, its a game where you step on arrows in order according to the screen. I have gotten better at it and can play the faster songs and work up a really good sweat after about 4 songs.
Actually many universities are studying the game made by Konomi Digital. They are trying to incorporate it into a child's school life. During phys. ed most students would play that game instead of baseketball. Some kids don't enjoy sports, but all enjoy games. I say in the next 5 years a lot of schools will incorporate it. Some in West Virginia already have.