KBS definitely took dance battles to a whole different level for today's show! The greatest of today's kpop groups performed and definitely put on a show that no one can forget! Kickin' things off was SHINee and their rendition of Lady Gaga's Just Dance! Kara turned the sexy on with Janet Jackson's Son of a Gun. SNSD kept the Janet Jackson trend going with their rendition of Rhythm Nation. 2PM got their groove on, showing their awesome moves with the Black Eyed Peas' Boom Boom Pow. Super Junior rocked it out to ??? ???. And finally, all the groups came together to perform a mashup of 2009's greatest hits!