Arduino Uno
From bildr
Overview
The Arduino Uno is an Arduino board almost identical in looks, size and shape to the Arduino Duemilanove this board however has the capability to make full use of the USB protocol thanks to its Atmega8U2 (which replaces the FTDI Serial to USB chip) meaning that it can "pretend" to be any other USB device, for example you could program it to be a mouse, keyboard, flash disk, printer or any other USB device.