If anybody has the energy to go clubbing 'til dawn--then hit campus for an early-morning class--it's college students. That's why so many college students are starting businesses as club promoters. Working with local club owners, students promote the clubs by handing out fliers and coupons of the "get in free before 10 p.m." variety.
To make it as a club promoter, you've got to know the club scene, and serious schmoozing is a requirement. The more people you know, the better chance you'll have of getting a big draw at the door. Most promoters get a percentage of the take at the door, so in a single evening, students can rake in several hundred dollars.
Promoting also means a lot of late nights--once you've gotten people in the door, you've got to work the room and entice them to go to your next club event. Start-up costs are minimal, but you need lots of charisma to convince club owners you can host an event and bring people in.