While Microsoft has already confirmed that they are not going to release any Windows 10 Preview Build until end of this year, they are stil l sharing their updated builds with their partners. We recently reported about Windows 10 Build 9888 which includes updated animations and context menus, changes to Settings app and more. Watch the video demo above. This build got leaked on the web and you can download it from file sharing sites.
Since it is not an official build, download and install it at your own risk. There might not be clear upgrade path to future Windows 10 builds.
You can find information to download the build here.