If you upload a screenshot from the game to your Facebook account, you can unlock a Minecraft Theme for your Xbox 360 dashboard. Instructions below:

When playing, pause the game and press X. Then enter your Facebook info in the boxes and press OK.

It will upload the screenshot to your Facebook page and you will have also unlocked the Minecraft theme.

Go back to your 360 dashboard, go to Social, and click on the avatar that is yours.

On one of the pages it says 'change theme' - click on that too, and go down until you see the Minecraft Wood Theme.

Press A on that and you have an amazing dashboard!