Raspberry Pi Foundation has announced a partnership with Microsoft who will offer Windows 10 for Rasberry Pi: Blog entry
"Today the Raspberry Pi Foundation announced the retail availability of their new board, the Raspberry Pi 2. We’re excited to join the Foundation in also announcing that Windows 10 will support Raspberry Pi 2, which will be free for the Maker community through the Windows Developer Program for IoT later this year."
Wow! Which board makers will follow?