The name of this piggy bank tips you off that it isn't actually intended for children. But we think the physics lesson you might get every time you put a coin in the top is worth considering it for collecting your kid's college savings.
This bank imitates, on a much smaller scale, a hyperbolic funnel, which you may have seen in a science museum. When you start the coin spiraling at the top, gravity slowly drags it in a smaller and smaller circle with a faster and faster velocity. (If you are a science teacher or a scientist, please forgive the possibly inaccurate use of technical terms!)
At any rate, it's a bank that makes putting money in a fun experiment, or at least a mesmerizing little show.
Available for $75 from Fitzsu.