I saw a wheel with a cassette on one side of the hub, and 3 chainrings on the other side of the hub. Does anybody know what that is? Is it some kind of weird flip flop hub?

Here's a link. Anybody know why that wheel is built that way?

It looks to me that he is showing the Biopace chainrings that come with the wheels by hanging them on the hub.

But look how far that axle or whatever it is is sticking out on both sides....

Sheldon Brown would know. And now that I've posted his name, his search engine will be sure to find this thread, and I'll have my answer.

i almost want to say that that's a tandem hub with a freewheel spun onto the drum brake threads.
but that axle!!!??

I'm shocked that I might possibly know what this is!
Manuped wheel!!! That's my final answer.

By George, I think our man John has it.