As part of the course requirements for the mechanics class I took, a team of which I was a part designed a Rattleback. A rattleback is a top that appears to have a preferred direction of rotation, i.e. if you start spinning it the wrong way, it (unintuitively) will turn around and spin “the right way”. There’s quite a bunch more to know about the physics [1] of it, if you care. It might also be an interesting dynamical system to study, as little is known about it past what can be found by numerical simulations. Speaking of numerical simulations, if you are a student of EN137 after me and would like to take a peek at our simulation code (which was written in Octave, with a bit of PyLinear sprinkled in), be my guest.
In any case, you may view the Rattle back, Rattleback! of our rattleback to see for yourself!
PS: I blatantly stole the title of this entry from one of the other teams. :)
[1] A. Garcia, M. Hubbard Spin Reversal of the Rattleback: Theory and Experiment Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 418, No. 1854 (Jul. 8, 1988) , pp. 165-197