Welcome to the penultimate "Ode to TED" day.
Siftables are an ingenious invention with amazing possibilities. My favorite part is the lack of need to explain the interface. Even though people have never seen them before, they will either know what to do from the beginning or have fun trying to figure it out. This is also one of Shannon's favorite TED videos.
TED2009: David Merrill demos Siftables (TED link)
(The length of this video is 7:12.)