Hektor: the Graffiti Robot
Lopex writes "Gizmodo has a story about Hektor, a graffiti robot. Apparently it is for the extremely geeky (or perhaps extremely lazy) tagger. Hektor.ch has photos, information (pdf), and a movie (15 Mb) of it in action."
A variation of an XY plotter, hanging from cables, gravity pulls it in the Y direction.
A friend and I did something practically identical years ago for a tech shop project in high school, though we werent allowed to use spraypaint, so we had it draw on walls with magic markers, like a giant hanging etch-a-sketch. Worked pretty well, and really wasnt that complicated to build (QBasic "driver" software included)
I don't need no instructions to know how to rock!!!!