Designed during Visual Language class at ITP.
Details of the design process can be found at my blog.
I wanted the cards to be PCBs. So, I designed the boards in Eagle and exported the gerbers. Then I changed the gerber file extensions to match the specifications on elecrow. I viewed the gerbers in gerbv. When I was sure that the boards look good, I made a panel of boards using gerber panelizer. I followed this great guide by hackaday for this. This is a lot easier than making the panels in Eagle directly.
As a result I was able to fit 2 boards in one 10x10cm panel. That's some serious savings!