Hiking is really easy to do, as is treadmilling. There's something soothing about seeing the miles traveled climb on a display as you keep walking. For something more intensive, I'm going to enroll in a fencing club at my college next semester. Nothing cuts calories than trying to dodge saber slashes though you can always try martial arts for similar effect; Karate, Tae-Kwon-Do, etc. are common examples but there are other ones out there (I want to learn Krav Maga but there are no teachers nearby). Maybe try something more extreme; quit playing Tony Hawk and go get a skateboard. Try jumping a bench or some other obstacle and work your way to more elaborate stunts. The point is you shouldn't lead a sedentary lifestyle as exercise will make you feel better because you'll have a better self-image about your body and because of endorphin release that exercise results in.