FIRA RoboWorld Cup
FIRA is most for above BA/BS level students and companies to develop their research in robotic field though robot soccer.
+ http://www.fira.net/
International Robot Olympiad
IROC is for students from under 8 to undergraduate students. It has been one of most popular robot competition for a decade.
+ http://www.iroc.org
Line Following Robot Contest
The Huntsville Robotics Group is hosting a Line Following Robot Contest to be held in October 2006 at the U.S. Space and Rocket Center located just east of NASA's Marshal Space Flight Center.
+ http://robotics.meetup.com/67/