What should I do with my old wedding ring?

I got divorced in August of 2008 and I still have my wedding ring. My ex didn’t want it back, and I just don’t know what to do with it. It’s beautiful and I’ve worn the small anniversary bands as rings by themselves without the engagement ring (with the big stone). I don’t know if I should sell it, have it turned into another piece of jewelry, or save it and use the stone in my next ring.