Josh Powell is giving a great talk about how to make single page web applications with JavaScript. The main focus is on how to break free of the web 1.0 tyranny of doing a page load for every new piece of content. He says his big AHA moment was to hang a handler off the jQuery hashchange() function; this lets you put a router on your client side; you can show different content based on the value after the hash without page loads, and your browser history buttons will work properly. Cool stuff.