Terry, I think it was Dee that has a couple of them that he brought to the Gatherings. They are really handy and fold flat for storage. I'm not real certain, but I think he said that Brad got them for him from Academic Sports. And then again, I might be totally mistaken.
It wasn't a CleverMade and it wasn't Pammie's stackables. It is hard styrofoam that is about an inch thick and snaps together at the seams like a puzzle. When you're finished, you unsnap it, fold it flat, and put it away.