I'd heard of this thing long before I heard it played, but I didn't know much about it and wasn't much interested. But a few years ago I went into a place on Frenchmen Street in New Orleans that was part of the Satchmo Summerfest evening fest, the Satchmo Club Strut. It's a fun event, with a wonderful variety of musicians and bands playing, for everyone to enjoy in the clubs and on the street.
One club, I don't remember which, had a guy playing jazz on a Chapman Stick with a drummer, and it was amazing. I was transfixed, fascinated.
The Stick looks like a wide electric guitar fingerboard with strings, but with no other instrument body. As I understand it, playing it is like the "hammering on" guitar technique, hitting a string with a left hand finger behind its fret to make the note sound without plucking the string with your right. Unlike a guitar, the Stick's pickups are so sensitive that this is the standard mode of playing it, with no need to pluck any strings, and therefore both hands can finger notes, and with great gentleness and subtlety. This lets the Stick be strung so that one player can cover bass lines, chord fill-ins, and the lead melody.
For me, it's fascinating to watch, and this guy Rob Martino shows how beautiful it can sound.