Verb. Sending a tweet or tweeting @someone more famous than yourself in hopes that they will re-tweet and make you famous for a few minutes in the twitter-verse. Opposite of 'down tweet' or "down tweeting".
A gathering of nerds attempting social contact, likely for the first time. Usually disintegrates into everyone running to the nearest computer to type to one another.
Tommy: Hey Jethro, quit playing WoW its time to meet some folks at the tweetup!
Jethro: Oh yeah I forgot about that, I can't wait to meet BigBootay421 at the tweetup, but first I need to slay this orc!
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.