CM10 Android Jelly Bean has been released for the HTC Dream or the HTC G1, the very first Android phone. http://www.engadget.com/2012/08/09/htc-g1-running-jelly-bean/
Symbolic of the greatness that is android....with great dev support and love for the platform anything is possible. Wow.
That's amazing, and really shows how flexible Android is. Looks like it runs at a decent speed (by 530mhz cpu standards). If I ever see a reasonably priced used G1, I might pick one up just for the novelty factor.
Android and this phone have only been out for 4 years. I actually had my gf at the time get the G1 simply so I could tinker with it.