questions
I love to question my students on present and past materials....keeps thm engaged!
it allways amazes me of student that when asking them a question of information past, that even if you think they are not paying attention that they often will produce a response to the question that actually makes sense
The only thing to keep in mind when organizing these sorts of competitions is to vary the teams involved.
I also like to pit one side against the other in compition this really gets everyone excited and they learn as they go.
also, if questions are asked in fun and interesting formats (ie Jeopardy-style), students will recall how much fun they had learning the information when the time comes to recall it; whether it be for testing or once they have graduated.