The Novation Circuit is actually an independent musical sketchpad that has it's own onboard drums and synths, and it works with your DAW like any standard MIDI controller.
No computer? No problem. The four–part drum machine and two polyphonic synths can be sequenced in real time or via steps. You can listen to your composition on the onboard speaker or plug in your headphones; this thing runs on batteries, so you are truly mobile.
Earlier this year we got a look at the Circuit during the annual NAMM conference, and we were blown away. After watching Ben A's video above, look back on our first impressions back in January: