I gave a D player a spot where all they had to do was make the 9 ball hit the end rail on any legal shot, that was pretty sick. I've also given up the one and the break before, mostly as a way to get action flowing, but it turned out to be an interesting game.
The sickest I ever heard of though was a top pro, who shall remain nameless, giving the 6 out, the last four, and the break and BIH to boot, and playing for $60,000 a GAME. It was back in the 80s and, according to the way I heard it, the guys were paying the pro and his backer off in bricks of cocaine after every five games. So sick if true.