Mahoney and Kaktus were also the two guys behind Noisetracker, the original demoscene tracker program (Protracker, the very first tracker, was a commercial program from Electronic Arts). So they really knew a thing or two about musicmaking, yes.

Defintiely look at His Master's Noise. It has 101 tracks by a number of composers, plus an additional eight in a hidden part. Plus there's a ton of easter eggs to find. And you'll never tire of playing around with the mouse pointer. Great design as PG says, and also Mahoney's farewell song to the scene as this is where he announced he was quitting it.

And after all that time I spent creating an entry for this some time back, PG linked to pouet. tsk, tsk.