Bandai's Aqua Dance water toy utilises some sort of nanotech coating to send endless balls...of water cascading through a maze. I feel the urge to pee just thinking about it.
When the water balls have finished their journey through the maze, they are sucked back into the water tank to be reborn once again (haha...innuendo). So, it's kind of like a water fountain, only way more sciency. The device should be available in March for roughly $US40. [Bandai via C Scout Japan via DVICE]