Several months ago, Dusjagr; my friend from Swiss introduced me to a powerful micro-controller called BabyGnusbuino in a workshop at lifepatch. Developed by A N Y M A, BabyGnusbuino is a micro-controller compatible to Arduino environment with USB interface. It’s very easy and cheap to make one. However, it have less feature such as I/O pins (of course) compared to a normal Arduino board, but it’s very useful for people which only use micro-controller for simple applications. In short, BabyGnusbuino is simpler version and cheaper of an Arduino board.
It’s quite easy to make one, you just need several components, etch a single sided PCB and burn the bootloader. You will also need to download the Arduino software to program it.
All the source code can be downloaded in: http://gnusb.svn.sourceforge.net/viewvc/gnusb/branches/gnusbuino/
All about Gnusbuino can be found on SGMK wiki here: http://wiki.sgmk-ssam.ch/index.php/Projects#Gnusbuino