HTML 5 is the newest form of HTML to use in rendering and formatting web pages for use on the World Wide Web. This site will provide some interesting examples of HTML in use on the Internet, including Video and Canvas use. HTML 5 also offers easier to understand layout creation, with HTML 5 websites making use of the <header>, <nav>, <section>, <article>, and <footer> tags in lieu of the typical <div> tags common with today's websites.
HTML 5 is currently a work in-progress, but thankfully has been implemented by most browsers. Below is a picture of the new features in HTML 5.