You are about to lose the game.

Rules of Play:

If you think about the game, you lose.

Point of controversy: If somebody else has thought about the game in the preceding fifteen minutes, you do not lose the game (a) period (argued by the Platonists), or (b) if the person who has already lost has informed you of this loss (argued by the Nihilists).

In the Platonic view, loss of the game exists objectively: we cannot know for sure if we have lost, but to a good first approximation we can have some information about who has lost recently.

In the Nihilist view, on the other hand, loss of the game has no basis other than in the eyes of the beholder, and therefore, not only do you not lose if you refuse to play the game, but you do lose if you are unaware somebody else has lost.

It is also a point of debate whether one is required to announce a loss of the game. The Kantians argue that one is required to do so but may refuse; the Empiricists argue this is a contradiction in terms.

Yet another area of controversy revolves around the issue of continuous thought or discussion of the game--i. e., do you lose if you're thinking about the game more or less constantly for fifteen minutes?

Also, do you lose if you refuse to play? The Existentialists say no; the Platonists and Kantians say yes.

Some people, known as Wobblies, claim that the grace period is, in fact, five minutes. Slokums reject this view and maintain that there will be one standard and better it should be fifteen.

One final point of debate is over the capitalization of the game's name. Naturalists argue in favor of non-capitalization, while Mooglists argue for capitalization. A third, radical, amorphous group opposes giving name to the game, and has been termed by some "Antinomenclaturalists"; most adherents of the ideology refuse to be labeled.

Origins:

Murky, but thought to have originated around the turn of the 21st century CE.

NB: The Game seems to have ballooned into an Internet meme of sorts since this write-up.