9. Psy. By now, everyone knows Psy's claim to fame. It's his viral hit, "Gangnam Style" People everywhere have been listening to the song and trying to learn the hilarious dance. Glee covered the song and fans have been creating parodies left and right. Madonna and MC Hammer have both performed live with him at various events. The video for his song is now the most viewed video on Youtube. How crazy is that?!