From the MechaniCards web site:
MechaniCards™ are miniature, hand-operated, kinetic sculptures, designed and produced in limited edition by Bradley N. Litwin. Each one is hand made, numbered and signed by the artist. They are constructed primarily from paperboard, with a few bits of wood, metal, or plastic. They make excellent gifts, and are suitable for mailing, as truly unique greeting cards. Each piece comes with complete instructions and display recommendations. They are also available as do-it-yourself construction kits.
Here's where you can learn more about and order your own MechaniCards.
[ Thanks Ron! ]