Steps to creating such a "game" could be as follows:
- Gather musicians/instruments into a room.
- Select one of the musicians to be the "Composer."
- Make a series of cards which are adorn with symbols that have pre-determined meanings. The symbols would signify general musical ideas such as: "play something fast," "play something low," "slow the tempo," etc.
- The Composer would collect the cards and begin presenting them (at their discretion) for the other musicians to play to.
The results of this would be Aleatoric music.
Here is the link to the John Cage piece that I showed in class:
http://www.youtube.com/watch?v=AJMekwS6b9U
Here is a link to an Aleatoric water instrument video:
http://www.youtube.com/watch?v=CZ_KijiwQHE