HTML5 is currently under development as the next major revision of the HTML standard.
There are lot of radical improvements in this version.Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third-party browser plug-ins such as Adobe Flash and Microsoft Silverlight.
If you are a multimedia developer just like me(videos, drag&drop features, more interaction), you will like this.
You can find more information here.
hope this interest