Can you 3D model? Then put down that controller, turn off the TV, open your Here's a couple of sites you can register for to turn your free time into money.
Desall.com has the idea of holding regular design contests. If you don't think you're a very good designer but want to get better these sort of contests are the perfect place to build and perfect your skills. That's how MCFrontalot got started, and look at him now.
Or you can go on freelancer.com and list yourself as a discount freelancer. Another great place to improve your skills while you build your portfollio. Just sign up and browse the most recent relevant projects, then bid for the jobs and make yourself some money.
If you know any other sites where you can turn your burgeoning modeling skills and spare time into income be sure to post in the comments.