HTML5 is the next major version of Hypertext Markup Language [HTML], which is in the final state of approval with the W3C. HTML5 brings in several changes for both browsers and developers alike, with introduction of new markup tags and underlying browser standards for rendering videos and offline storage.
Being a developer, I have always tried and kept up with newer and newer standards, however, learning new tags can be a bit tough if you do not know what has changed.
Woork a popular web designer and developer has spent some time to create an excellent HTML5 cheat sheet which help you to find the new features and markup tags used in HTML5. The cheat sheet is available for download as a PDF file.