My mom just told me a story last night about this girl that she was friend's with in college. The girl had gone away for the weekend, and when she came home the entire house smelled like male cat urine. She searched the entire house thinking he had sprayed, and when she got to the bathroom she found that he had been urinating IN THE TOILET all weekend long. After that she learned to keep the seat up and to flush often!
It's the only toilet-training-cat story I've ever haerd of personally, and it's even cooler because the cat taught himself!