The Technical University of Denmark is soon holding its annual robot competition "robocup" and the deadline for entering is on Monday the 17th of March. The actual competion will be from the 8th of April to the 10th of April AFAIK.
The competition is an excellent opportunity to meet other robot builders and to try out your robot creation in a competition where you can actually earn some money even if you don't win. Line following is a major thing in the competition since a line leads most of the way through the course so if you have something that can follow a (black) line you're already set to go.
Don't be put off by the fact that this is a university sponsored competition. Of course there will be some really neat robots in the competion but many of the robots are built by people that are just getting in to robotics and so their robot's capabilities are somewhat limited (I have entered the competition with two extremely limited robots and it was fun and educational).
Robocup spans three days where the first day is where the course gets set up and where you can play with it all day (and night). Day two is qualification day where usually the 15 robots with the highest point score proceed to the finals on the third day. After the finals you can usually go and grab a beer with your fellow robot builders and talk about what went wrong and why you didn't win :-).
Rember... you don't enter competitions to win but to learn and have fun! :-)
- Jimmy