Given all the fuss about the Mayan calendar, I thought it would be fun to look at other times when people thought the world might end.
Saint Clement (c.90 CE) predicted the end of the world was imminent (probably influenced by Paul).
Bishop Hilary of Poitiers (c.300-c.368) was called the "Hammer of the Arians" for his opposition to them. He claimed in 365 that Emperor Constantius II (a semi-Arian) was the Antichrist, and the Apocalypse was imminent.
Hilary's student, St. Martin of Tours (316-397), claimed the end would come by 400 CE.
Hippolytus (170-35), sometimes called the first antipope, was a great scholar who thought 500 CE was a good round number for the end of the world. The historian Sextus Julius Africanus (c.160-c.240) also thought 500 was a good round number for the end times.
In 968 CE, the army of German Emperor Otto III saw an eclipse and widely believed that the end was nigh.
In 992 CE, Good Friday (a "floating" holy day) coincided with the Feast of the Annunciation. This concurrence had been thought to be a sign of the end. A report came from Germany that the sun rose in the north, and that suns and moons were fighting in the sky. Other countries missed that sight.
In May of 1000 CE, Charlemagne's body was disinterred in order to fulfill a legend that an emperor would rise from his sleep to fight the Antichrist.
A belief that Jesus would return 1000 years after his death made people look to 1033 CE as a date for the beginning of the end.
Pope Innocent III, scholar that he was, added the legendary number 666 to the date of the founding of Islam, and concluded that the end would come in 1284 CE.
The Black Death was seen by many as the end.
...and so on.