You've got a boat, an astronaut, a preacher, a snafflecow, and a pitbull. All need to be ferried across the Grand Canyon. You can only take one at a time, but you can't leave the snafflecow with a Canadian, the preacher with an atheist, the pitbull with a sleeping child, or the astronaut with another astronaut. Furthermore the snafflecow always lies. You have only one diaper between you.
Go. You have five minutes.