There are quite a few gorgeous new Jabo JOKER marbles on eBay right now, many from a single 15 hour "run" on May 18th 2008. I am surprised by the variety that was produced in such a short run.
It is exciting to see machine made marbles like this still being made in America. These rare beauties are truly instant classics and most collectors seem to agree.
You can find out more about Jabo and these JOKERs over at the Jabo Land discussion forum.