Gimmicky techniques such as upside-down and multiple discs are obvious, and hence pretty boring. As far as disc manipulation goes, I like to take two copies of the same disc and tape them together back-to-back so that the beats line up perfectly. This way you get some cool reverse echo effects on the drums. As far as actual performance goes, I often combine chord buttons to get a wider range of harmonic possibilites. Results vary depending on which disc you’re using, but generally you can get major 7th chords by holding Bb & Dm, F and Am or C and Em.