I've already kind of mentioned it in my "Meet My Kitty" thread but here is the story of Jin:
My brother crashed at my house for a short while due to unfortunately breaking up with his missus, and he brought along a very small, very skinny female cat that was losing her fur. She was also infested with fleas, and covered with various scabs and infected places, but she was INCREDIBLY amorous and would give you this beautiful little meow when you came towards her. Unfortunately as I had two of my own she was confined to the spare room (and was given various toys) as I couldn't risk the spreading of fleas.
One afternoon, when I agreed to look after the cat until my brother found a place to live, I gave her a thorough looking over to see just how bad she was. She turned out to be a boy, hidden by the cllumps of matted hair around his bottom, and obviously infected ears and nose.
When I told my brother, he agreed to let me take care of the cat and, with the help of my vets and the Cats Protection League, we got him de-fleaed, de-wormed, hair growing back and got rid of infections in his right eye, his ears and his nose. He's now quite a furry, chubby little fella with a very independant character, but is also very loving and gets along well with my other two.
The vets were amazed by how unhealthy he was, and how skinny. His growth is a little stunted because of his previous problems and his teeth are a little decayed but otherwise he's quite happy now, and we've named him Jin