They'll do math.
"Forgot to carry the Pi, its actually 2019 that the world will end......"
But seriously...what happens everytime a predicted doomsday doesn't happen?
[edit on 22/5/09 by madhatr137]

The Hopi prophecies play an important part in the multiform weave of traditional stories. The rich oral traditions, which resist orthodox or dogmatic interpretations comprise various versions and interpretations of the prophecies available from different individuals of different clans and villages. They are evolving stories that guide the interpretation of contemporary events. However, Kaiser (1991, 83ff.) has pointed out that the different versions have certain things in common. The most important of these may be the assertion that human beings have the choice between two ways of life: the traditional Hopi way and the way of the white man or Pahana. These two ways are also labeled the "path of the one-hearted" (the traditional path of balance) and "two-hearted" (the path of progress and imbalance). The traditional Hopis, who are at times also called "hostiles" or conservatives, see themselves as the stalwarts of the one-hearted path that follows the original instructions from the Creator; they see the Hopi Tribal Council following the path of Eurocentrism and progress, the path of the two-hearted. Another common assertion among the different narrations of the prophecies is that many Hopis leave the good path of the original instructions, leaving a simple and prayerful life behind, and follow the mistaken path of modernization.
The different versions and interpretions of the prophecies all state that this world will come to an end. The time before the end will be marked by chaos, confusion, fear, and suffering. Elders see the present-day destruction of the environment, the disappearance of plant and animal species, the World Wars, and the threat of nuclear holocaust as giving rise to fear, despair, and dread. Indeed, in their view the end may come soon, since certain markers mentioned in the prophecies have already occurred. One such marker is the "gourd of ashes" understood as the atom bombs dropped on Hiroshima and Nagasaki. Another common prediction is that a powerful figure will return at the time end of the world. This person of central importance is called Pahana (also spelled Bahana, Bohana, or Bahanna) or Elder White Brother, and he was also present at the beginning of this world.
In all versions of the prophecies it is stated that at the time of the end of this world there will be a period of purification and judgment. The survivors of that process will receive salvation. However, few people will survive, and there may only be one or two Hopi persons who have not left the one-hearted path behind and who have held to their original instructions from the Creator. Those individuals will be the beginning of the human world that follows this one.
Another common feature among the different tellings of the prophecies is an understanding of time as marked by regular cycles of purification, marking the endings and beginnings of worlds. Future developments can be anticipated because of similar events in previous worlds. The time cycles are understood as determined by the Great Spirit at the beginning of this world; the stone tablets given to the Hopis were engraved by him and hold the record of the original instructions and future events. The first world was destroyed by fire, the second by ice, and the third by a flood. Purification on each of those occasions was necessary because the people had left the path of the one-hearted behind, did not honor the agreement with the Creator consequently became degenerate due to affluence and technical innovations. As a result of the materialistic or two-hearted way of life, they behaved in immoral ways. no longer lived with respect for nature, and no longer sought balance in the proper ceremonies.
The final common feature that Kaiser identified among the different prophetic narrations of the Hopi people is that the destruction of the world is not inevitable. Instead. people may cleanse themselves individually and of their own choice. This would mean that individuals remember the original instructions given by the Creator. Masa'aw, and they would thus return individually to the path of the one-hearted or the traditional way of the Hopis. This would effect an alternate transition to the next world.