Rolando Fuentes made a pretty cool MIDI e-drumset.

The brain of the drum pad is made using a Teensy-LC and 2 multiplexers.  You can use Garage Band, or almost any other music program to play your new drum set.

The drum pad is made using velostat and  a matrix of copper tape.

The code for the project as well as detailed instructions can be found on this Instructables page.