If you're proficient in a specific subject and you enjoy (or at least don't hate!) teaching, you can tutor other students at your school.
You can be a professional web surfer by testing websites for companies wanting to improve their online capabilities.
If you enjoy writing, consider blogging for bucks. It will take some real work to get it started, but if you can find a unique angle to draw readership you can make money.
Find out if there are groups on campus with a common interest and offer (for a fee) to make all the arrangements for a trip to the destination of their choice.
Looking for more crazy ways to earn money? Ziprecuriter estimated that working full-time as a test subject can earn you over $80,000 annually.