1. Gangnam Style
Korean rapper Psy's Gangnam Style video has been watched almost a billion times since he rode his invisible horse onto YouTube in July. He's duetted with Madonna and everyone from Britney Spears to Ban Ki-moon has gone Gangnam Style in public. Between Psy and YouTube success story Justin Bieber, it makes you wonder why the X Factor is still bothering.
The ditty - mocking Korea's affluent Gangnam area - has everything needed for a viral monster; a catchy hook, natty outfits and a ridiculous, temptingly imitable dance. Psy performs those equestrian-inspired moves deadpan. He's got the clothes of 50s Elvis and the attitude of Freddie Mercury. The meme potential is seemingly endless - 'Gandalf Style' being a popular parody.