This Kata is based on the Gilded Rose Kata, originally created by Terry Hughes (http://twitter.com/TerryHughes). It is already on GitHub here. See also Bobby Johnson's description of the kata and this version with multiple languages. It was slightly rebranded by Axxes IT Consultancy, and renamed to Gilded Tros (with a wink to a local bar near the Axxes HQ ;)).

The simplest way is to just clone the code and start hacking away improving the design. Instructions can be found in the GildedTrosRequirements document.

Have fun and good luck!