Nick Bostrom, a professor at Oxford and director of the Future of Humanity Institute, presents the Simulation Argument. More about the idea can be found on the on the Wikipedia page, and you can see more about Bostrom on his TED Talk profile page.
Here’s a fascinating panel discussion from the 2011 World Science Festival. It’s a group of physicists and computer scientists discussing the deep nature of reality and how it relates to computation. The overview page has more info.