The point when, after having been awake for an extended period of time, a person becomes unusually hyper and loopy, somewhat mimicking the effects of being drunk. Usually lasts anywhere from 15 minutes to an hour, and is almost always followed by a harsh crash.
After being awake for 30 hours, I was so pillowdrunk that I couldn't stop laughing at the word "bubbly".
An excellent decision. Are you bored with the usual mumbo-jumbo your grandparents talk about? Bring alcohol into the picture! It will spice up any conversation, and your grandparents will either think you're a degenerate, or a comedy god.
"(Being drunk at dinner with your grandparents) is the best thing I've ever done!