Totally Nuts!
*sigh* I'd might as well post this.

I invented this one afternoon, I was playing around with different methods on a lark and this is what it resulted in.
Roll 4d6 7 times dropping the low die each time and dropping the lowest score.
Always reroll 1s.
You may reroll 2s, if two or more of them are rolled.
You may reroll 3s, if three or more of them are rolled.
You may reroll all 4s if four or more of them are rolled.
You may reroll all the dice if you get a straight.
If you roll identically with two consecutive rolls, the scores from the two rolls can be traded for an 18 and the lost score is rerolled. This applies only to the final numbers and not what they were before certain numbers get rerolled. It can also apply when you roll a straight, identical to the straight you are rerolling.
Of course this "method" of rolling scores is nutty as hell and not to be taken seriously. The worst you can get is a 9 unless one of your dice spontaneously combusts. My lucky *grumble* players rolled high enough for my campaign without using this, so I don't think I'll be letting them use it. It's just for fun.
Interestingly enough, when I showed this to a friend of mine it gave him the seed of an idea for a fantasy board game, which he's currently working on.