I'm really curious about this as well. The lecture is from 2008, so it's entirely possible that he or someone else has solved it by now, and I'd really be curio

I'm really curious about this as well. The lecture is from 2008, so it's entirely possible that he or someone else has solved it by now, and I'd really be curious to know what the answer is. It's such a simple system of marbles and magnets, so it's pretty incredible that such an unintuitive thing would happen. You'd also expect that, given the simplicity of the system, any weird behavior would have some elementary explanation (elementary to trained physicists and mathematicians, anyway), but apparently not. Stick around for the end of the video where he demonstrates an equally incredible and (at the time of the lecture) unexplained phenomenon with "chiral tippe tops".