Friday night - youth group – session all planned – materials all ready. It's the moment of calm before the storm when you pause to pray and wonder how it will go this evening. Will they get into it? What kind of week will they have had? What range of moods will they be in? And then they're here, filling the room with sound and energy. Two of the boys are talking tactics for their latest PlayStation game. Three of the girls are huddled together giggling and whispering, excluding everyone else from their conversation. Lucy looks subdued and isn't...