What are the legal stipulations for holding an event?

Yea, you will need to file an application for a temporary business license probably. So you need to contact the city and ask them what type of forms they need you to fill out, and there is probably a fee. If the admission prices are charged only to pay for the costs of the even itself, maybe it will be cheaper than if you were trying to make a profit, but each city, county, or where ever you are planning to hold the event has different requirements for that.