I always have a copy of Emmett's brilliant Gear Bearing out on the coffee table - it's such a great talking point and introduction to 3D printing - and recently someone I showed it to suggested it might make an interesting bangle. I'm not sure about its fashion-worthiness, but as a printing challenge I thought it was an excellent idea.

I had already used an idea by Sal to print gear bearings with large circular holes instead of small hexagonal ones (http://www.thingiverse.com/make:26306), so I just took this up to the next level. I have posted the modified .scad file so the design is still fully parametric, and also a copy of the STL file that works with the tolerances on my printer.

Here is the video of the bangle working as a gear bearing (but not as a fashion item!) http://www.youtube.com/watch?v=Qt39vLo5l90