15th B-Day Party Ideas

Hi,
I`m turning 15 on January 14th, and i have no ideas of what to do for it. I`ve done bowling, restaurants, partys, sleepovers, panting, we can`t go swiming cuz we live in the SB Mountains and its very cold.it`s going to be like 10 people and coed cuz my boyfriends got to come and like 3 other guys the rest are girls. My invites have to go out on the 8th, so i really need some ideas ASAP.
Please HELP.
Thank You,
Michelle