We talk to the kids every night while they're gone. And we check with my mother in law to find out the real truth, or to make sense of the babble the littlest one gives us (he's one of those people that it's much easier to speak with him when you're in the same room).
They were having a hard time falling asleep the other night. Desperate, my mother in law told them that the first one to fall asleep got a dollar. She heard not one more peep out of them until morning.
My children will do nearly anything for a dollar. I guess that's why they won't ever find my keys for me - I only offer a quarter.