San Francisco-based artist/coder Robert Hodgin of Flight 404 Blog created some of the most mesmerizing sculptures using magnetized balls and cylinders. They're part of the Gray Area Foundation for the Arts (GAFFTA) exhibition.
That has got to take some mad skillz because I can easily envision the whole thing collapsing into a pile of magnetized blob at the slightest touch.
MAKE Blog has the gallery: Link | Robert's official webpage
Related: Buckyballs over at the NeatoShop