Microsoft will be releasing the latest version of their operating system named Windows 8 very soon and infact it's already available for download for MSDN and Technet subscribers.
For the unlucky ones like me has the option to download a 90 day evaluation of the same from here
Before you go for downloading, you have to take a note of couple of points
This evaluation version will expire after 90 days and wont be able to upgrade.
It's better to go for the installation in a virtual environment so that it will be easier for you to upgrade from your existing version. Otherwise you will have to uninstall the evaluation first and then do an upgrade.
Inorder to the get the link for the download, you have to should have a Microsoft Account and should also activate the product within 10 days of installation.
You have options for 32-bit and 64-bit versions...