From NCL website: 'complimentary activities happen every day- whether your child wants to paint, have a pajama party or put on a show. And just think of the new friends they'll make- you might even have to schedule time just to see them.' 'Our complimentary kid's and teen's clubs give the kids time to explore and meet new friends, while you relax, have fun, grab a bite, go shopping and more – it's all up to you.' see http://www2.ncl.com/freestyle-cruise/freestyle-family-fun/kids-crew-and-teen-crew
Sorry but that is not entirely true. It is free on sail days but on port days it is $6 per hour. I have only one child, but would assume that this charge is per child.