Mathematical toys?

For when the Möbius strip is too pedestrian, the good people at Acme Co. claim their Klein bottles are the "finest closed, non-orientable, boundary-free manifolds sold anywhere in our three spatial dimensions."

On Shapeways, you can find a variety of mathematical ornaments.

My favorites are the differential geometric surfaces designed by Bachman. I also like Bathsheba's designs as well.

(Sorry the image is so large. Is there a way to reduce the size?)

I have a Rattleback at my desk. Fun to fiddle with while thinking.