1. Re purpose them for gift tags. For Christmas, use a cookie cutter to cut a shape and simply write your "to" and "from" on the card. Punch a hole with a one-hole punch and tie on a piece of scrap string, ribbon, yarn, or cording.
2. Simply punch a hold and tie on a string, scrap piece of yarn or thread. Use as a Christmas Tree ornament.
3. Punch holes all the way around the playing card. Single crochet through every hole, making a Christmas Tree ornament.
More Links to more Playing Card Crafts, Projects or Activities:
Playing Card Classroom Valentine Treats
More Playing Card Classroom Valentine Treats
Instructables: Playing Card Case
Free Kids Crafts: Playing Card Tote Bag