craftgrrl | what to do with bottle caps?

I've found that our house has been accumulating a whole whack of bottle caps lately, mostly from Smirnoff coolers & beer bottles (specified since apparently there are a lot of different kinds, which I didn't know about before looking for ideas...)

What are some interesting things that I can do with them? I'm thinking more along the lines of wearable crafts as opposed to hammering them into doorframes, which I can't do anyway since I live in student housing.

I tried searching the journal (didn't work for some reason) and Google mostly told me "Frames! Stamps! More frames!", which didn't grab me.

ETA: How do I secure two caps to each other, faces out? Should I glue or use some cool hardware trick? And to flatten them should I simply pound them with a hammer, or would having my friend drive his car over them be a bad idea?

Thanks!