Boyfriend's graduation tomorrow... Gift ideas?

I know it's short notice but my boyfriend of 1 year is graduating high school tomorrow. I need to find a little gift to give him after the ceremony! I've been so busy that I completely forgot, so I need to ideas. He is almost 19 and he absolutely loves nature and being in the outdoors. He's a total workout junkie and is obsessed with his car. He also loves home-made gifts, I've made him a collage of all his favorite things, painted him a picture, and wrote him lots of poems, and cookies (of course). I'm completely stumped on what to give him next! It needs to be just a little trinket that I can either make or buy without a hassle since it's on such short notice. Any ideas? :) Your input is much appreciated!