When David Staal shows up for work at the weekend services at Willow Creek Community Church in South Barrington, Illinois, it's "game on." Between one Saturday night service and two Sunday morning services, he will oversee 1,000 children's volunteers and 3,000 kids in Promiseland, the megachurch's children's ministry.

"Our mission is to make Promiseland the best hour of every child's week," says Staal. "To do this, our ministry has to be safe first and foremost. Safety is one area you can't ever compromise on or the whole ministry is at risk. You need to bat a thousand every time."

The center of an expansive, open-air foyer for Willow Creek's main auditorium features an indoor waterfall. A staircase leads down to the base of the waterfall, which is the entry point to Promiseland. It's here you'll find Staal warming up for the game.

"Before every service I stand in the same place and pray, 'God, keep our kids safe today.' Hundreds of parents have entrusted us with the most important thing ...