Here's a nice little gift for the person who likes gears, levers and things that move, they're called MechaniCards, from Brad Litwin of Kinetic Works. A little paperboard, bits of wood, metal and plastic and all in something about the size of a greeting card. I like the radial engine the best. You can get them assembled or as a DIY construction kit. Pretty cool.
Related: Kinematic Models – Mechanisms in Motion