13th Surprise Bday Dance Party For Boys & Girls Help!

So I`ve rented a teen center to host a surprise 13th birthday party for my daughter. I figure about 50 kids at the most. It has a sound system, disco ball, lighting system, etc. All can be hooked up to an ipod. There is also a pool table and foos ball table. DO I need to plan things for them to do or can I just turn up the music, feed them and just let them have fun for 2 hours? Also, what would be a good party favor? Do I need favors?? All help is appreciated. Also have to be budget conscience as hubby lost his job recently. Thank you!