Menards has a Wen generator for less than $300 I think. I doubt anyone has an extra laying around, unless one of your friends fathers has one you can borrow for the night. But you have to be real careful running your lights and stuff for it. You don't want to electrocute yourself, and you don't want it grounding into the water and shorting out the genny.

Make sure your boat is safe and up to USCG-standards. I.E. fire extinguisher, loud horn or whistle, life jackets for everyone in the boat, navigational lights, etc.