Mathematical toys?

Anybody know of "serious" mathematical ornaments or toys like the Gömböc, etc?

Already have a rubix and abacus (that's more of a tool though).

Solution 1:

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."

Solution 2:

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?)

Solution 3:

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

Solution 4:

The Rubik cube. ${}{}{}{}{}{}{}$

Solution 5:

Spirograph from Hasbro. You can make lots of famous mathematical curves with its pieces: epicycloids, hypocycloids, etc. MathWorld has an article on some of these curves.