To allow everyone to participate, the attendees were divided in three groups: Ninjas, Pirates and Zombies. Each group would solve the minesweeper challenge using the randori approach and at the end each group had a chance to show their solutions.
Another interesting approach for this dojo was providing a common set of cucumber stories to guide the development. Matt Wynne wrote them and also provided a rake task to help keeping the TDD flow by encouraging people to solve the tests one-by-one (source code is available here). As a result, all the groups managed to solve the challenge in less than one hour, giving them enough time to experiment alternative solutions and refactorings.
Although there was no general retrospective at the end of the session, reading the feedback on the LRUG mailing list it seems like people enjoyed the experience. Personally, I really liked the fact that everyone participated, probably because they’re used to the language and tools and knew each other from previous LRUG meetings.
Well, maybe is time to start organising public dojos again.