Here's a fantastic drumming robot that was on display at the recent Russian World Robotics Olympiad.
It listens to a rhythm that is clapped at it, and then repeats back the same pattern. Not bad in itself from a group of students, but I think the best part is the fact that it expects some congratulations after it has performed. Clap enthusiastically, and it'll smile for you, but if you don't give it any applause, it'll show a frown.
The robot consists of two NXT's, one for the drumming hands and one for the head. The drumming hands also have the sound sensor, and the routine for playing back the rhythm is written in NXC. This NXT also figures out if post-performance applause has occurred and send Bluetooth commands to the head NXT to display the correct emotion.
Full translation here - http://translate.google.com/translate?sl=ru&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fnnxt.blogspot.com%2F2012%2F05%2F2012.html&act=url
Big thanks to reader Alex who sent this through to us!