13th Sep is celebrated as 8-bit day which this year marks the 30 years of Super Mario Bros. Microsoft too celebrated and wished Happy 8-bit day with a nice Easter egg.
Here are the details how to crack this Easter egg:
↑ ↑ ↓ ↓ ← → ← → B A
that is up, up, down,down, left, right, left, right , b,a (this is the Konami code which was the famous cheat code appearing in many Konami video games) I think it works only on US version, so use the above link only.
- and you can see a pixelated version of Ninja Cat riding a T-rex across the screen at bottom and it will be dropping coins.


- And you’ll also see pixelated ‘Insert coin to play’ . Just drag one of the coin to the slot and the user will be greeted with a message from Microsoft ‘Microsoft.com wishes you a Happy 8-bit day!’

Its very nice Easter egg, give it a try. This Ninja Cat has become very popular after Microsoft started using this as a sticker. Recently similar T-Rex GIF animation Easter egg was seen in Skype too.
EDIT: Microsoft sent invites to its Windows 10 devices event which had some binary codes on the image. On cracking this, Microsoft links to a webpage with a new ninja cat wallpaper #Windows10Devices | Blogging Windows
Go to the above link to get the full sized wallpaper.
(Source:meraTechPort)