Forget electronics, the coolest thing in robotics may just be something squishy like a walking gel that inches along just like a caterpillar:
Shingo Maeda and colleagues made the colour-changing, motile gel by combining polymers that change in size depending on their chemical environment. This is based on an oscillating chemical reaction called the Belousov–Zhabotinsky (BZ) reaction. The result is an autonomous material that moves without electronic stimulation. [...]
Polymers used in the gel shrink and grow in response to ruthenium bipyridine ions, alternately losing and gaining electrons in the cyclical reaction. That effect has been known for some time, but hasn't been used to make a self-locomoting material on such a scale before, says Maeda.
Link (with video clip) - via Cliff Pickover's Reality Carnival