Show off the musical talents of your student body by hosting a battle of the bands. Announce audition days and times. Have the student council (or the whole student body) vote on which bands enter the battle. Ask permission to use the auditorium as the concert venue on a specific day and time, making sure that you’ve lined up students or staff to help out with mics, speakers, etc. You can even create a printed program for the event.
In the weeks leading up to the battle, sell tickets for the price of a donation to your fundraiser—make sure to collect names or hand out tickets with each donation. You can also sell tickets at the door using a mobile device.
Obviously, the success of this event hinges on the quantity and quality of bands at your school. If the audition yields too few bands for a good show, consider pulling the plug. Alternately, you can consider similar fundraising ideas for your student council: perhaps a poetry slam, rap battle, dance-off, or other performance competition.