A pretty badass fan-made TMNT short set before the first movie (which was awesome).
From the creator:
My idea was take on the world before Shredder arrives. In my version Shredder would be more of an evil genius that takes over a common street gang and trains them into the organized clan later seen in the films. I’m a huge fan of TMNT but at the same time felt the world needed a different take than was previously established.