I'm late to the game on this one, but I really, really do love both the concept and the bots. I have to post it just to show my support.
Tweenbots are human-dependent robots that navigate the city with the help of pedestrians they encounter. Rolling at a constant speed, in a straight line, Tweenbots have a destination displayed on a flag, and rely on people they meet to read this flag and to aim them in the right direction to reach their goal.
tweenbots | kacie kinzer
(via Timbot & Czeltbot)