Boy Surface, in my favorite projection. It's in a network form, partly to cut down on volume but also because the whole point is to be able to see the internal structure.
Looks very nice in WSF. There's a little imperfection at the bottom where the outside becomes the inside, but that's the nature of the shape.
Very slightly updated model (after it has been here for years), to address some "thin wires" problems Shapeways is having. Almost identical to original, but hopefully will print better.