I've been kicking around the idea of designing and etching a USB business card. USB business cards have been around for a few years and there is a few designs and software options to choose. My plan is to use an Atmel microcontroller to open a browser and direct them to my website. There is a few issues with this idea as Windows doesn't like to execute code from USB since this could circumvent security. But, I am not at this stage and will tackle that later on.
I have started designing the schematic and there is nothing exciting about the design. It's just a minimal microcontroller circuit, but may add some LEDs for show. I chose the ATTiny85 as it's common with loads of firmware examples.