15th Birthday Party

For my 15th birthday party, i invited a couple of boys and girls, but im not sure what kind of activities to hold because everyones kinda old for little kid games although im cool with them:) anyone got any cool ideas? i would really appreciate it! So far, i have karaoke planned out, guitar hero, COD, outdoor activities like sports, but since my birthday is on winter, idk if i can have outdoor activities...please help!!!!