3.Mommy and Daddy are taking a nap.
Only those who are parents will understand the double entendre behind this little white lie. Yes, Mommy and Daddy are in the bedroom, but no, they're not really sleeping. When the bedroom door is closed, most children have been told, don't come in without knocking. What goes on behind closed doors doesn't have to be shared with the youngins, right? Of course, as kids get older they usually figure out why Mommy and Daddy's bedroom door is closed. By that time, the "ick" factor keeps them from barging in.