My daughter is Director of Community Service for her HS student government. Her committee had to come up with a fundraiser for Common Ground (http://commongroundhelps.org/). Their idea was accepted: each teacher will have a piggy bank in their classroom. Students can donate money. The teacher who raises the most money will be "kidnapped" for the day and the student government will pay for their substitute. The teacher will be able to have the entire day available for learning and planning.
Very cool way to raise money AND give teachers more time to do their job well.