What should I get a Twelve year old for his birthday?

Ok, his birthday is June 3rd and I'm his girlfriend, yet I'm still clueless what to get him. He's in to soccer, skateboarding, and he's pretty mature. I'm 11, going on twelve next January. I know he's a bit older than me. Anyway, he also loves Twix. My mom said I have to keep it under 70$. Any ideas? Thanks!