Interesting top designs? (the spinning kind)

So I need to get my brother-in-law a gift, and I’m not supposed to spend much money on it. Spent a while in the bookstore yesterday and didn’t find anything inspiring, so I’m thinking of making a top. See, he has a collection of all manner of different sorts of tops. Stacking tops, tops that turn themselves over while spinning, a “perpetual motion” top (battery in the stand it spins on keeps it going indefinitely), and many others. Hence, if I’m going to make him a top, it should be a bit out of the ordinary. I have access to a lathe and am reasonably competant at using it, so production isn’t a big deal, but I’ve no really good ideas for what, precisely, to make.

Any ideas?

I know you were looking for designs you could make, but I thought I’d give you a heads-up on Tetra Tops.

Maybe for next Christmas. . .

Well, there’s nothing particularly unique about them, but here’s a tutorial on turning tops. Pick some exotic enough woods and an interesting profile for the edge of the disk and you should have something rather nice.