In my interactive systems class, we recently had an assignment to make something with either a laser cutter or a 3D printer. I ended up making a fairly simple pad out of wood on the laser cutter:

index-card-holder-1.jpg
index-card-holder-2.jpg

The design only took five minutes or so in Illustrator, and Iā€™m fairly happy with how it turned out. (I do think having an engraved area in the middle for the index cards to sit in would help, though.)