Many of us are still getting use to using the newly released Internet Explorer 9 but Microsoft isn't resting. The company has recently made available the Internet Explorer 10 Platform Preview.
Much like the IE9 Platform Preview that was released before the browser's beta, RC, and final release builds, there isn't a whole lot going on with the IE10 preview at this point. There isn't any real UI to play with and no amenities like tabbed browsing, though you can run Microsoft's HTML5 demos, including brand new ones like Fishbowl, an update to the original FishIE tank.
There are several other tests avaialbe that show off some of the HTML5 and CSS3 features as well as speed demos showing off gpu acceleration. You can run these at www.ietestdrive.com to see emerging standards like CSS3 Multi-column Layout (link), CSS3 Grid Layout (link) and CSS3 Flexible Box Layout (link), CSS3 Gradients (link), and ES5 Strict Mode in action. MS also demonstrated additional standards support (like CSS3 Transitions (link) and CSS3 3D Transforms (link)) that will be available in subsequent platform previews of IE10, which we will update every 8-12 weeks.
For more details checkout the IEBlog -
Native HTML5: First IE10 Platform Preview Available for Download