There is now (and I believe will be only for a limited time) a trackable deck of paying cards - here is the information (as taken from the forums for trackables - posted by COWWS:

The Official GeoWoodstock VIII Deck of Cards is now for sale!!!!

The playing cards are designed by various geocachers from all around. You can see all of the cards here.

$12 for a deck that is trackable w/icon! (the deck is trackable, not each individual card )

All deck of cards will be available for pickup at the Information Booth at
GeoWoodstock VIII on July 3rd, 2010.

If you're not attending GeoWoodstock VIII, we'll send you a Paypal invoice for shipping and send them out after July 5th. We're a bit busy until then!

You can purchase the Trackable Deck of Cards HERE

I think these would make great Christmas gifts, silent auction items and who knows. Certainly not to be released in a cache but something fun to play cribbage when out camping.