When you pick a song to listen to in the Zune software on your desktop, you can click a little EQ looking icon in the lower right of the screen and get a really cool screen... This works in your library or even browsing and sampling in the marketplace.

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Here is what you have when you click it...

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This screen uses album art from your collection as the background. Really Slick!

To get back, hit the backspace on your keyboard, the back button on your mouse, or click exit in the same place the EQ icon was.