Bradley Litwin creates mechanical greeting cards. They are curious, limited edition, small kinetic sculptures that you power with a tiny hand crank. You can see them in action in the above video.
If you have the urge go to the section of his website called MechaniCards were you can order one or more of his cards. It is part of his main site Kinetic Works where you can view his kinetic sculptures dating from 1979 to the present.