My version of a patrol Llama. Original from Lego NXT site, and actually this got modded significantly after the picture (front wheels made no sense).
The first version came from http://mindstorms.lego.com/en-us/News/ReadMore/Default.aspx?id=136785
I subsequently modified it a bit mechanically and created a patrolling program for it. Part of the program (or at least something like it) is up near the end of: http://fller.pbworks.com/ParcMeeting20100404
The Llama actually randomly patrols in different directions [looking for something to spit at], so it is slightly fancier than that program. If you want the full version, I can send it to you. And in about two weeks there should be a version on the web after the kids dissect and document the bots (see Robot Activity #2 at http://fller.pbworks.com/ParcCourse)