In patrols (or whatever explorers split themselves up into) re-enact the dining philosphers problem which is used in computer science to illustrate avoidance of issues when sharing a resource.
1 bowl of spaghetti / pasta / rice per patrol, 1 fork or chopstick per scout. Tables you can sit round in groups of say 6. Chairs. (Dishcloths and surface spray), whistle
First see -- See http://en.wikipedia.org/wiki/Dining_philosophers_problem -- and for an animation see -- http://www.onarat.com/. Cook a bowl of pasta/spaghetti/rice per patrol (add tomato sauce if you want to add to the fun) Place it in the middle of a circular table and seat the scouts around it. Explain the dining philosophers problem as per wikipedia description (show the animation too if you have internet access). Give the scouts philosophers names if you want to. Blow a whistle to start the system off. The scouts follow the rules given in the description of the problem. . Get the tables to call out when they have reached deadlock (i.e. when no-one can access two forks and therefore no-one can eat) or when one scout is fed up with not being able to eat at all (e.g. for a minute). Tell them some of the ways this has been solved . Get them to restart adopting one of the solutions. Tell them that this is a problem faced by computer systems everywhere where more than one program shares a resource. Who knows if they'll understand, some might, but it should be fun to try.