Lego Technic Spider!  583 elements, 2 M-Motors, Theo Jansen style legs, and IR remote control.  Each motor drives the legs (and pedipalps) on one side, allowing the spider to go forward, back, and to turn.  I've posted a video of it in action at http://www.youtube.com/watch?v=RZ64D2znuOo.   Photos are also at  http://www.flickr.com/photos/arcanemettles/.    

Tags:  

Lego 
Technic 
Power Functions
MOC
Spider
Arachnid
Robot 
Walker
Theo Jansen
Black 
Lime 
Red