Robots Waltz on a Pinhead

From The Future of Things (w/ pics!):

Researchers at the Donald Lab at Duke University have built miniature robots, only a few microns tall, capable of acting in concert to achieve collaborative tasks. This ability was recently demonstrated by orchestrating a dance to a Strauss Waltz between two of the spatula-shaped constructs. The group has tied as many as five robots together under a single universal control, the most complex system of untethered microscopic robots ever created.