One thing Microsoft have alway been kicks ass at is desktop themes and wallpapers.

I had my homepage as Bing for a while just because of the gorgeous daily pictures.

Here is a great one, Remix 3D Animals, from the Remix3D team.

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Or how about Paint 3D Creatures?

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These are delivered through the Windows Store, take a look at a bunch of others here.

The Xbox Team can also serve up wallpapers in various different sizes for your device.

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Halo 5 anyone?

Check out the range of games over on the xbox site here