Have you ever realized that quiet noise is actually your child? I know, my child isn't a noise in my ear, but as parents, you learn how to tune in when it's necessary. The Boy is behind me, about ten feet away playing with something, I think part of a Mega Block robot fighter thing. It's basically Mega Blocks' tragically sucky answer to Bionicles.
He is also playing where most of his Thomas stuff lives, so I'd assumed he was playing with the engines. I can hear him as he plays, but we are the only ones home, so his playing has a quiet personal note that's not usually possible with Big Brother here also.
What finally caught my ear as he was playing was him repeating something. I don't know how long he'd been saying it when I finally realized he was saying, "exterminate, exterminate" in his best Dalek voice. Next came the sound of someone being exterminated. And I never really thought he paid that much attention to Dr. Who. Big Brother will watch it with me and actually has reminded me about it. What great kids!