Sydney Universtiy runs a Robot wars leauge, which is part of SUMO – the Sydney University Mechatronics Organisation. Everyone is welcome to participate, even if they don't know anything about robots or (gasp) even if they aren't doing an engineering degree.
Competitors form groups of between 6-8 people, and will work together over the year to create a fighting robot that will compete against other local teams in the final competition at the end of the year. To help teams along, the society arranges regular sessions with guest speakers, offers sage advice from ACFR robot experts, and encourages teams to work openly with each other and share ideas and expertise. Additionally, throughout the year, there are frequent 'mini-competitions', which allow teams to field test their robot before the final competition. These take the form of robot sporting events such as racing, tug-of-war, bowling and wood-chopping (so don't worry about breaking your robot before the final event).
If you feel you don't have the time to participate in a team, there are also many other areas that you can help with if you still want to be part of the action. The arena team is in charge of creating traps and hazards for the final competition, and there is an ACFR house robot that people can contribute to. SUMO also hosts BBQs, fund-raising chocolates, raffles and other fun events to raise money to cover costs of the robots.
Also, don't forget that this year the best robots from the USYD competition will go on to compete in the Official Australian Robot Wars Leauge!