This is the real reason Anakin Skywalker went to the Dark Side. Obi-Wan had a half-brother named Kobe-wan Kenobi. It happened one cold and lonely night on Coruscant, while Anakin was in tormented meditation about his love-that-couldn't-be for Padme, as Kobe-wan came to "comfort" the young Jedi-in-training. Well, one thing led to another...and we're left with a pervert that leaves disturbing messages of heavy breathing on holograph-answering machines.
Now, I haven't seen Episode III yet, but I'm pretty sure this is what's going to happen.