Introduction
This page covers alternate ZAR rules which for one reason or another I have decided not to include in my "standard" rules.
Touching the Playpile
Rule
Variation A: You may indicate that you are playing a card (or Match) by touching the corner of the Playpile with the edge of your card.
Variation B: You may indicate that you are playing a card (or Match) by touching the Playpile with your finger. You must immediately play a legal card from your hand after you touch the Playpile; failing to do so is an illegal play.
Advantages
As described in Basic Strategy, it is desirable to avoid having two players bend their cards or bang their knuckles as sometimes happens when a play and a Match occur simultaneously. Just touching the Playpile to indicate that you are going to play now avoids this collision. Once it is determined which player touched first, their card can be placed on the Playpile without interference.
Disadvantages
Both variations reduce, but do not eliminate, players bumping into each other. Both variations make it MUCH harder to determine who gets precedence on a close call. Variation B does a better job of reducing collisions, but has the undesirable side-effect of giving players much too long to think about which particular card they want to play after they have touched the Playstack. This results in an overall slowdown in the pace of the game. Moreover, I think that being compelled to quickly decide between several legal plays makes the game more fun and offers another opportunity to reward fast players.
Super calling MATCH
Rule
Simply calling "MATCH" before the current player plays will take precendence. You must immediately play the matching card from your hand after you call "MATCH"; failing to do so an illegal play.
Advantages
This rule reduces players bumping into each other. It also provides a more "even playing field" if there are infirm or disabled players in the game.
Disadvantages
It is much, much quicker to look at your hand and call "MATCH" than to physically reach out to the Playpile. This rule results in a large disadvantage against the current player. In an average game, a Match will beat out the current player virtually all of the time. This rule not only completely neutralizes an intentional design decision to reward fast players, but also introduces a huge bias in an otherwise even contest (playing verses matching). Unless you have some very special circumstances, I strongly recommend that you do not play with this rule!