Don't drag them to 'leadership camps' without telling them at least a half-truth about where they're going. Then push them out of the car, and speed away while they stand there in utter disbelief.
One of my highschool friends, her mum used to do that all the time, a group of us would be sleeping over at her place, giggling, eating popcorn, talking about girly things, and her mum would come in and yell "LETS PLAY TRUTH OR DARE!" and said friend would be completely humiliated.