Not really... but a pretty convincing Gaga look-a-like was performing, however (sorry). IK Multimedia has a bunch of cool music-making app and accessory products covered by our iPhoneLife musical types over the years, but the booth here at CES was jumping. My personal favorite was the iRig MIX and DJ Rig app combo. A mini mixing board that let's you scratch like a pro (not that I would understand exactly what that is)...
