RoboCup is an international robot soccer competition that has been running since 1997. A frequent criticism of any such competition is that all of a team’s development is narrowly focussed on a very specific task and consequently, little contribution is made to science. In this paper, we describe our involvement in the RoboCup four-legged robot league and show how the competition has, indeed, resulted in contributions beyond robot soccer. We describe innovations in vision, localisation and locomotion. In particular, we discuss the stimulus that RoboCup has given to system integration and cooperative behaviour between multiple agents.