HELP!

Hi. I`m 13 on very soon and i cant think of an idea for my birthday. I want something small, but i want it with lots of my friends. I don`t want a disco because alot of my friends are having really big ones and I`m not too sure i can pull off a big one like them. My mum thought of going to cadbury world but i can only take 5 of my friends ( because we can`t all fit into 1 car) i really don`t want to leave anyone out. I want to invite about 10 people, i also want something to remember because it`s my thirteenth. PLEASE HELP MEE!!

X :)