Apparently there is a bird and his nest in the vent that goes outside from my water heater, so the carbon monoxide couldn't get out and came back into my house. Lovely.
I spent the morning in my pajamas, standing on my driveway, waving down the fire trucks that had the wrong address.
Not a dull moment, and I don't even have kids!
Get a detector and put it above the doors in all bedrooms.
*Image from svennnn on flickr