iRig Keys 37 USB MIDI keyboard controller for Mac/PC by IK Multimedia

http://www.ikmultimedia.com/products/irigkeys37 for more info.

Powerful. Portable. Affordable.

Concentrated compact creativity. You want it? You got it. iRig Keys 37 is an affordable, ultra-portable MIDI keyboard controller for Mac and PC that lets you practice, perform and record with your favorite software anytime and everywhere. Its 37 velocity sensitive mini-keys make for a keyboard that's the perfect size for the mobile musician — you get a 3 octave range (plus 1 note) in a compact enclosure that you can use to jam at home, on the go and anywhere in between.