A real genuine spokeless bicycle
I've seen tons and tons of pictures of spokeless bike wheels. But it's always been from industrial designers who haven't done much bike riding, have never wrenched a bike, and who have no idea about what's possible or practical. Sometimes they claim that it's somehow "freeing" to not worry about such things, but I tend to think that there's a fine line between genius and stupid.
Anyway, some engineering students actually made one. I suspect that it's not the sort of thing you'd be comfortable riding a 200km brevet in, but at least they built it in real life instead of in a design program.