The new Arduino prototyping kit allows you to build and program your own circuits using the fully functional and production-ready Arduino prototyping board.

The BlinkM packs an ATiny85 micro controller, which allows it to be flashed with the Arduino bootloader thanks to the people over at the [High-Low Tech group at MIT].

[Walter]’s device was based upon the Arduino Leonardo. Starting with the Caterina bootloader, modifications were made to enable the device to be locked and unlocked for programming.

At about $30, the Arduino isn't an expensive device, but if you want to make your own, simpler version, electronics blog Hardware Startup shows off how to build an Arduino clone for less than $5.