In our house "OK - time for bed" will send 2 dogs madly rushing upstairs. I have to admit I have used that during the day when I want to mop the downstairs floors!
Also the sound of car keys will have 3 dogs doing the "happy dance" at the back door. It does not matter if I am actually going anywhere - I can just move the keys and it will get that reaction.
Dogs are amazingly perceptive. I am just so thankful that they can't talk! A friend of mine was telling me about her African Grey Parrot who will mimic things it hears said in the house. I think it is hysterical that her bird will call the dog by name and tell him to "sit"! I say way too many bad words to have anything mimic me.
Karen