Cardeasy helps someone hold and organize a hand full of cards and also has a nice stand so you can sit it down and still see the cards, without displaying to others.
You can find the original design drawings and STL's attached. I printed this on a Makerbot Replicator 2 using medium makerware settings, 2 shells, 10% fill, and without support standing upright but I am sure it will work on many other 3D printers. You can find it on thingiverse as well: http://www.thingiverse.com/thing:95818
The gap is pretty tight and may have some burr from printing, which if not removed may scratch the cards. I used a utility knife to clean out the gap as well as some fine sandpaper.