I thought it would be worthwhile to mention a couple of new resources that we've put up recently:
First, we've put up a step-by-step tutorial on building courses for line following and maze solving. The tutorial shows you how it's pretty easy to build great-looking courses for a few dollars out of electrical tape and posterboard.
On a related note, the 3pi User's Guide now includes sample code for basic line following and maze solving; the complete C source and project files come with the AVR library download.
Hopefully, the tutorial and example code will get more people excited about building robots and setting up contests!