World's Fastest Computer

http://www.ibtimes.com/articles/166542/20110621/world-s-top-10-fastest-supercomputers-of-2011-tianhe-1a-china-k-computer-japan-nasa-supercomputer-ja.htm

According to the link above, the fastest computer is the "K Computer" in Japan. It is located at the RIKEN Advanced Institute for Computational Science in Kobe, and is capable of performing over 8 quadrillion calculations per second. It is supposedly more powerful than the next five most powerful computers combined.

According to "How stuff works", the "human brain" is the fastest computer, though. I would find that a legitimate answer, if the human brain were a computer (although who is to say it's not?) However, the website very roughly estimates the brain to be able to calculate 10 quadrillion instructions per second, and considering how rough of an estimate that is, the K Computer might even be able to beat that.