Create beats and music in all sorts of ways with Ableton Push. She won't work with legacy versions, but absolutely smokes with LIVE 9. Just in case you don't already have the latest version, Ableton has snuck a copy of LIVE 9 INTRO in the package for you.
Back to the hardware - there's touch sensitivity all over the 64 pads, manufactured by Akai Professional, including aftertouch. It's basically a square gridded keyboard controller, with zones for manual play and step sequence.
Plays happily with Mac or PC, and there's a host of features, like adjusting the swing of your patterns that are dead simple to use. Stop reading and have a squiz at the video below.