Customizable LED morse throwie firmware for Attiny45 & Attiny85. Can be used to make something like this.
This is an Eclipse project. You need the AVR Eclipse plugin and the AVR-GCC toolchain to compile and upload it. On Windows, the easiest way to get the toolchain is to install winAVR.
A good step-by-step guide on how to assemble the throwie can be found here.