One of the questions raised was: "How on earth does this thing work? Does it actually sense its surroundings, or is it just a glorified 90's Dancing Coke Can?"
The Infanoid Project says:
Neat touch to actually place the cameras in its eyes and letting it "smell" sound! Still, the most important thing may be observing just how alive this thing seems, despite looking like a pair of tennis balls. One can communicate emotion with very simple means. (Eureka!)
Keepon has a yellow snowman-like body. The upper part (the "head") has two eyes, each of which is a color CCD camera with a wide-angle lens (120 degrees horizontally), and a nose, which is actually a microphone. The lower part (the "belly") has a small gimbal and four wires, by which the body is manipulated like a marionette; four motors and two circuit boards (a PID controller and a motor driver) are installed in the black cylinder. Since the body is made of silicone rubber and its inside is relatively hollow, Keepon's head and belly deform whenever it changes posture and when someone touches it. (more + pics)
And here's a cute, little music video for those of you who missed it.