Today, I was introduced to the coolest musical instrument I have ever seen: the theremin.
It was actually invented 90 years ago, but somehow has not gained enough popularity for everyone to know about it (perhaps because it is Russian). It is an electronic radio frequency instrument: you play it by moving your hands closer of farther from two antennaes: no keys, no strings. Check out some cool videos on youtube (just search theremin).
It kind of makes you wonder what else you haven't heard about...