That is cool, sounds like percussive tuned didgeridoo's for lack of a better description, nice rhythmic feel.
This guy was ref'd in Youtube on the page so, I gave it a click,
http://www.youtube.com/watch?v=phqym...eature=related
Those glasses have got to be filled with water though, tuning them with vodka sip by sip would get a bit tricky after a bit
Homemade Instrument 
