13th Birthday

Hi Everyone-
My birthday party is tomorrow. I have invited around 30 people to go to the beach and hang out under a canope tent, with music (i dont know what kind the place picks). There will be pillows and lots of food, along with a Fire. There are some people... Like my close friends that i know would be ok just doing that the whole night but im not sure about other people. Got any ideas about what i can pick up that would be fun to do? I dont really like the whole organized game thing... The people my grade really dont like to do stuff like that, they like to amuse them selfs in weird ways... Turth or dare is good but we are on the beach so got any other ideas?!