One of the most contagiously funny group exercises that I guaranteed to warm your group up, and have them in fits of laughter, presented by Mark Collard / www.playmeo.com - the world's leading online resource of play & adventure-based learning activities.
Air Lock teambuilding game. This would be a great game to play with kids to practice leadership skills. You could have the students take turns being the one in charge and giving the group directions. Leadership is another vital social 21st century skill. I would use this in any subject classroom.