I think often they were best with questions. If you showed them that you would take their questions seriously, they would start bringing you serious questions. But they were genuinely interested, that was the thing. They really did want to know. The older students tended to get a jaded, 'why do I have to learn this?' attitude about an awful lot of things.
*nods a lot*

And as for the course we did, then we had a few tricks for breaking down barriers. Firstly, we'd always start with something daft (an electric dancing cow, a chair-swapping game, a clip from Indiana Jones) which they then had to try to link to the week's topic (at around the halfway point they began to get the hang of it, rather than stare at us as if we were mad). Then we'd do a talk-thing about whatever the topic was, and then ask "What do you think?" [pause for scuffling of feet, wherein we tried not to say "DO you think???"] "Seriously - what do you think? Is this right? Do you think it makes sense? Why would the church believe this? Do you believe it? (It's OK if you don't, as long as it's your decision)" and so on. But I swear, helping those children to think for themselves about what faith actually meant, and whether this was something they agreed with, (rather than - as they were clearly used to - making sure they 'knew all the correct answers') is one of the most rewarding things I've ever done.