The AVR heart was a project I adapted to work with an ATTINY2313. The original project used an Arduino. I like the Arduino and all but its expensive, large and overly complicated for what I want. I wanted something I could fit onto a single piece of protoboard. I adapted his design straight up except I replaced the Arduino with some resistors for the LEDs and an ATTINY2313. Pink LEDs, an ISP header and a usb cable (strictly for power) finished out the package.
I wish I had better pictures but I gave it to my ex-girlfriend for Valentines Day 2009 and she has since moved to Georgia.
Here is a little video of the finished product.
Download the source code. I have to thank jaypee4227 on instructables as I adapted his code to work with the AVR.