I saw a friend using a couple of these to hold all her various drink-stamp cards (you know, those Buy 10 Get 1 Free cards that you have millions of and can never find when you need it). I immediately went to Target and picked two up. It's meant for business cards but I use them for the many gift cards I have. It keeps everything in one place, and you can fan it out to easily find the card you're looking for. So handy!
I keep business cards from vacations and study abroad in here. It's like a little scrapbook of memories.
The perfect solution for the myriad of business cards I have lying around for people I don't remember but may need to contact someday.