Zickos, you'll find it on this page: http://www.offthemark.com/cartoons/drummer/
A couple of the others are funny too ... the liver, Willie's ancestor (ha!) and intellectual property.
I wish I'd thought of the "boom boom" idea - it would have been funnier if the drummer was reading his page just like the others ... seriously interpreting the boom booms.
Or was he looking nonplussed because he was expecting proper drum music but some clueless buffoon of a musical director has just notated his primitive notion of drumming??