A.D. 4000 is a space warfare board game with a combat resolution rule that makes it a lot like space Chess. It is a pure strategy game, and the uncertain element is created by a blind movement system that I like to think of as a plot device.
Here are the most official tournament rules for the game of Checkers, also known as Draughts. Rule 15 changed my entire perspective on Checkers making it one of my favorite abstract pure-strategy games.
"15 All capturing moves are compulsory, whether offered actively or passively. If there are two or more ways to jump, a player may select any one he wishes, not necessarily that which gains most pieces. Once started, a multiple jump must be carried through to completion."Rules for Draughts(Checkers)
I've started a couple of interesting discussions at boardgamegeek.com, and each received quite a few responses and examples of board games using certain types of rules.