Meme
A term that first appeared in the 1976 book The Selfish Gene by Richard Dawkins that is defined as: "a unit of culture transmission, or a unit of imitation." A meme or viral meme is an idea, thought, question, or statement that spreads rapidly and is often used as a reference when talking about something.
- Rocketboom has a great collection of meme videos here.
Also see: All your base are belong to us, Buzzword, Godwin's Law, Rickroll