How about scanning each card and then placing them in a power point presentation. Add who the cards were from, and a bit about that person to make it more personal. You can add so much to the presentation using music, personal pictures, and your own touch.
You could also try getting a large binder and some clear plastic pages. You can slip the card inside the pages and place in the binder.
The minimum would be to affix each one into a scrapbook by putting glue on the back. Be sure to put dates on them and add information so that nobody has to rely on memory to know who was who. Memory always goes. Then if you want to fancy it up, you can glue confetti around them, or before glueing the cards for that matter, but at least get the minimum done. They are important and you are a gem to be willing to do this. Should take about half a day.
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