Calvinball

The sport invented by Calvin of the Calvin and Hobbes comic strip, which has only one rule: You can't play it the same way twice.

Other kids' games are all such a bore!
They've gotta have rules and they gotta keep score!
Calvinball is better by far!
It's never the same! It's always bizarre!
You don't need a team or a referee!
You know that it's great, 'cause it's named after me!
You wanna...

-- Calvin

Ball game invented by Calvin and Hobbes. Rules include:

1. All players are required to wear a Calvinball mask. This regulation is not to be questioned.
2. All following rules may be changed, amended or deleted by any player involved at any point in the game.
3. Any player may declare a new rule whenever he/she wants. This can be done audibly or silently, depending on the zone the player is in.
4. The Calvinball may be used in any way the player sees fit, whether to cause injury to other players or to gain benefits for himself.
5. Any penalty legislation may be in the form of pain, embarassment, or any degradation the rulee wishes to execute upon the other player.
6. The Calvinball field consists of areas, or zones, which are governed by a set of rules declared by players. Zones may be appear and disappear as often and wherever the player decides. For example, a corollary zone would enable a player to make a corollary (sub-rule) to any rule already made. Or a pernicious poem place would require the intruder to do what the name implies. Or an opposite zone would enable a player to declare reverse playability on the others. (Remember, the player would declare this zone oppositely by not declaring it.)
7. Players may name flags, assigning their powers and the rules governing the use of the respective flag.
8. Songs are an integral part of Calvinball and verses must be sung spontaneously through the game when randomly assigned events occur.
9. Score may be kept or disregarded. In the event that score is kept, it shall have no bearing on the game nor shall it have any logical consistency to it. (Legal scores include 'Q to 12', 'BW-109 to YU-34, and 'Nosebleed to Pelvic Fracture'.)
10. Any rule above that is carried out during the course of the game may never be used again in the event that it causes the same result as a previous game. Calvinball games may never be played the same way twice.
11. A Calvinball may be a football, volleyball, or any other reasonable ball.
12. The Calvinball field should be any well-sized field, preferably with trees, rocks, grass, creeks, and other natural obstacles.
13. Other optional equipment includes flags, wickets (especially of the time-fracture variety), and anything else the players wish to include.

Source: Comprehensive Calvin and Hobbes (http://www.geocities.com/SoHo/Nook/2990/index.htm). However, this is *not* a cut-and-paste job.

Calvinball must have a ball. That is without question. Otherwise it is not Calvinball that is being played but Calvinsomethingotherthanaball. It must also be a reasonable ball. You have to be able to actually play with the ball. Generally, a ball larger than the hands of the smallest player would not be eligible. Calvinball does not necessarily have to have Calvin in it, however. In fact whoever's playing can choose to name it after themselves if they'd like, but if someone asks if they're playing Calvinball, the players can choose to say yes or no if they so desire.

The real fun to Calvinball is making up new rules. Said rules are immediately canon to the game even and especially if they conflict with other rules that already exist, at which point clarifications and other rules must be put into play in order to make the rules work together none at all. Punishment for failure to successfully accomplish whatever the rules establish should be embarrassing or painful but not much so and they should also be fun and involve a lot of running around and breaking things that will get you in trouble with the parental units later.

What a shame it is we can't operate this way in the real world.

Closely related to the card game Mao, despite being different in almost every conceivable way. On the other hand, this being different is true between individual games of Mao, and of Calvinball. So this may be more of a similarity than a difference. Er... let's move on. ;)

There is one critical distinction (which I think I may mention, even under the rule of Mao): There are reasonably standard rules to Mao, and when they change at all, the rules tend to accrete, rather than being continuously reset as in Calvinball.

The other major difference is that it is almost impossible to actually play this game unless one person is all of the players. Calvin could get away with this when playing with Hobbes, but Rosalyn had trouble, as shown above. Of course, with a poor Mao-master, Mao is almost impossible to play too.