Watch the demo then play to win prizes. Play every day until June 30.
https://microsoft.promo.eprize.com/windowsphonedemo
https://microsoft.promo.eprize.com/windowsphonedemo
I think they changed it back again. If you have the default browser setting to "mobile," all you have to do is spin the wheel (click on the tile form the MS store app). If you have the browser setting to "desktop," you have to do the demo first. Glad they finally fixed it.
I have been playing since it was first posted here: Spin the wheel with the Microsoft Store Windows Phone app and win prizes | Windows Phone Central but as of yet I have not won anything. Once they changed it from spinning the wheel to using the demo, I have not been able to use my phone to play. Bummer.
I've also tried it with 2 Microsoft accounts since it was posted on WPCentral. All I got was a constant apology letting me know I didn't win.