Do you have an idea already?
But if you think you can somehow improve or expand upon the stock project assigned to you in class, then by all means work on it in your free time...the worst that can happen is you learn more programming (oh no!).
As for general advice, talk to your peers about the idea (I assume they are working on the class project as well) and get as much feedback as possible. Maybe they'll see something you didn't which may or may not motivate you to continue working on your idea. Talk to as many people as possible and you may find a partner through your research (don't worry about others stealing your idea so long as you keep all the really juicy details to yourself).
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+choose+part...
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+startup+loc...
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+incorporati...
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+startup+ide...
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+market+fit
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+merchant+ac...
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+startup+law...
http://lmgtfy.com/?q=site%3Anews.ycombinator.com+business+pl...