Why should you get excited about HTML5? Because it lets you run Quake II in your browser without any plug-ins.
The video above, which will work in any HTML 5 compatible browser shows just what is possible.
For those really having a geeky moment, in the port, they use WebGL, the Canvas API, HTML 5 elements, the local storage API, and WebSockets to demonstrate the possibilities of pure web applications in modern browsers such as Safari and Chrome.
Now stop camping and get fragging.