Oh gosh! I always say I am going to write these down and then promptly forget to!
One of my fav's is when we were riding in the car with my Dad (who is hard of hearing). My barely 2 yr old son pipes up from the back seat "I have to pee." My Dad didn't hear him so my son screams "I'm serious!" Cracked me up that he even knew the word serious much less the meaning of it.
My daughter said something not very kind and in a mean tone of voice. I was trying to explain to her that it was not nice and so on. I said "It is (and then I paused cuz I was trying to find the right words to use) and my then 3 year old pipes up "It's beyond rude! Isn't that right, Mommy?"
Both of my kids recently had some dental work done and my daughter told me afterward that her lip felt dizzy.
I too use their full names when they are in trouble. I said my son's full name and I heard my daughter tell him, "You'd better run Jack. Mommy means business now!"
The kids were fighting with each other and I walked into the room to stop it. My daugher says to my son very matter of factly "You go over there and sit in time out and I'll go over here and sit." Then she looked at me and said "Isn't that what you were coming to say to us, Mommy?"