We tried buying a plethora of new cat toys and giving them to him one at a time, replacing each "boring" one with a fresh new one. That worked for a couple days, but toys just couldn't compare with real "juice."
We were at last confronted with the ultimate decision: Ranger either had to go back to the shelter (where he would probably be unadoptable due to his rather bizarre habit) or we would have to start letting him outside. I didn't want an outdoor cat but, faced with the alternative, I decided it was the lesser of the two evils.
Ranger was petrified at first. I'd throw him outside when I caught him chewing on a cord and he'd cower under the potting bench on the breezeway until I opened the door again. Then he'd dart back in. After a few days, I saw him cautiously explore the yard a bit. By the time a week had gone by, though, our other cat, T.J., was green with jealousy and decided that he wanted to be an outdoor cat too. I tried to keep him in, but he got increasingly adept at sneaking out and I finally just gave up the battle. Once T.J. was outside, Ranger seemed to think that being outdoors was great fun.
Now they are both outside as much or more than they are inside. We try to keep them inside at night since we have cat-eating coyotes that roam the property, as evidenced by the claws I've found in their scat. So far, so good on that account. Ranger has become quite the ratter. I don't mind his thinning the cotton rat population, especially around the house and flower beds, but it is very hard to watch him playing with his prey for hours at a time before killing them. The ultimate cat toy, I'm afraid.
I've observed that most cats seem to become birders or mousers/ratters preferentially. Ranger has tried to go for birds, as the photo below evidences, but he's much more successful with the rats. That's probably best for almost everybody concerned...rats excluded.