There are two significant variations on the game of Mao.

For those unfamiliar, Mao is played (in my experience, which is therefore limited) with normal decks of playing cards. I say decks because if you have more than two people playing, you will quickly discover that a single deck is not nearly enough.

It runs much like Uno, in that, unless the rules provide, one card is played at a time...same suit on same suit, or same number on same number. The object (primarily) is to run out of cards.

Each round, the individual who ran out of cards first becomes the new "Mao", and may add a new rule to the mix, which they don't tell anybody about...it must be discerned from observation.

Additionally, questions as to the rules are not allowed, and questions are rewarded with penalty cards, which may not be played in the same round in which they are awarded. Not only does this keep players in the game for another round, but it also keeps them from asking questions on purpose in order to draw a card to play.

Now the important bit. If you're the kind of person who wants to encourage a fun game that people will keep coming back to play, a decent drinking game, something neat to do after a Magic: The Gathering tournament, or what have you...THE RULES DO NOT GO AWAY. As in, they never change in that they stop operating the way that they do, you just add to them.

On the other hand, if you are the type of person who likes games which drive people crazy, and generally feel that your job in the world is to punish people for not being your close friend, you may choose to change the rules at random as they amuse you, for the torture of others.

Everything else is negotiable. Bribery may be allowed, or even encouraged.

I have seen a game (which required us to create a new rule) where a single person was required to draw 96 cards at once. Play at your own risk.