I finally figured out how these beasties work!
My first one is a pentagrammic duoprism, made from two pentagrams.
Here's the page: Tuvel's Hyperdimensional Page
Here's the animation 5/2-5/2 Duoprism (DivX)
So, I'm closer to figuring out how to do the duocircle! (I think) Let me know what you guys think!