"LADIES AND GENTLEMEN!"--must have come from Dumbo, but one night he was literally yelling it from his bedroom.
"Let's do this thing!"--whenever we are going to ride his bike, or go somewhere
"Is that cool?"--NO idea where this comes from, but I crack up whenever he says it
"Giddyup Partner!"--he loves his rocking horse and also calls his cowboy hat his "Partner Hat". The one pictured below looks a little more like Minnie Pearl, but rest assured he now has a proper "partner hat" to ride with.