Six Potential EOW Scenarios, courtesy of Nature:

1. Killer comets and/or asteroids
2. Supervolcanoes (e.g., Yellowstone Caldera)
3. Supermassive black holes
4. Climate shift
5. Magnetic pole-swapping
6. Gamma ray bursts from nearby site (say, 3,000 light years)

Six Potential EOW Scenarios, courtesy of Science:

1. High energy physics creates stranglets
2. Uncontrollable nanobots
3. Super plague
4. Genetically enhanced class warfare
5. Artificial intelligence runs amok
6. Good ol' nuclear armageddon

Here's some past predictions about the End of the World (including The Rapture, etc.). If you want more info you can investigate them yourself.

ca. 1750 BC, Persia: Zoroaster.
634 BC, Rome: twelve eagles indicate that Rome will fall some.
389 BC, Rome: maybe this was the date indicated by the eagles, above.
167 BC, Babylon: Book of Daniel.
AD 70, Jerusalem: Rome sacks Temple
AD 90, Patmos: John writes the Book of Revelation.
AD 156, Phrygia: Montanus says New Jerusalem will drop down on Pepuza.
(all the dates hereafter are CE or AD, as you prefer)
365, Gaul: Hilary of Poiters schedules the EOW for this year.
500: Sextus Julius Africanus and other predict Jesus will show. Jesus doesn't.
April 6, 793, Spain: Beatus, a priest, says this is Der Tag.
950, France: Adso of Montiers predicts the End.
968, Europe: Major eclipse causes major panic.
989, Europe: Halley's comet.
January 1, 1000, Rome: Not much panic, except among literate clerics.
1033: It's a thousand years since Jesus was killed. No EOW yet.
1186, Spain: John of Toledo predicts EOW because of a planet line-up.
1260, Italy: Joachim of Fiore reschedules EOW for 1290.
1346, Europe: Black Death.
1420, Czech Republic: Taborites.
1504, Italy: Botticelli blows his prediction.
February 1, 1524, London: Astrologers predict world-wide flood, reschedules for 1624.
1525, Germany: Thomas Muentzer.
1535, Germany: Jan Matthys.
1537, France: Pierre Turrell says EOW this year, or in 1544, 1801, or 1814.
April 28, 1583, London: Astrologers say no flood, but a big wind.
1600, Germany: Luther says that this is Der Jahr.
1603, Italy: Tomasso Campanella says sun will collide with earth. Galileo declines to get involved.
1650, England: James Ussher says, "2000."
1666, England: Brits nervous (Great Fire, etc.); Shabbetai Tzevi.
Autumn, 1694, America: Johann Jacob Zimmerman
May 19, 1719, Switzerland: Jakob Bernoulli says this is the day.
1736, America: Cotton Mather blows it again, just as in 1697 and 1716.
1776, Boston: George III is the Antichrist.
1792, New York: Mother Ann Lee.
1809, England: Mary Bateman.
1830, New England: Joseph Smith.
1844, New England: William Miller.
1863, England: John Wroe.
1874, Pennsylvania: Charles Taze Russell
1900, Brazil: Antonio Conselheiro.
November 13, 1900, Russia: Brothers and Sisters of the Red Death.
1908, Pennsylvania: Lee T. Spangler.
1914, Oklahoma: Halley's Comet is back. Charles Taze Russell again.
1915: C. T. Russell.
1916: C. T. Russell (who dies on Halloween).
1918: C. T. Russell had said, before he died, "Really, folks. 1918.)
1920: J. F. Rutherford.
1925: J. F. Rutherford.
February 13, 1925, Long Island: Margaret Rowan and Robert Reidt.
1936, America: Herbert W. Armstrong mistakes 1936 for 1975.
1947, Boston: Oahspe Bible (1889) says "Yup. 1947."
1949: Young Billy Graham says we only have maybe a couple years left.
December 21, 1954, American Midwest: Dorothy Martin, a.k.a. Marian Keech and the Brotherhood of the Seven Rays.
April 16-23, 1957, California: Mihran Ask.
April 22, 1959, Waco, Texas: Victor Houteff says, "Here we are!"
February 4, 1962: five-planetary alignment.
1965-1968: Elijah Muhammed.
1967: Sun Myung Moon.
1969, California: Charles Manson.
1970: Hal Lindsey
1974, Indiana: Charles Meade & End Time Ministries.
1975: John Knorr, Charles Taylor (who says 1976, 1980, 1982, 1983, 1985, 1986, 1987, 1988 and 1989 as well).
1977: Salem Kirban.
1980: Ronald Reagan, James Watt, Caspar Weinberger, etc.
December 21, 1981: Hal Lindsey again.
1982: Jupiter Effect; Pat Robertson predicts.
1985: Lester Sumrall.
April 29, 1987: Dr. Leland Jensen.
August 16 & 17, 1987: Jose Arguelles and the Great Harmonic Convergence.
1988, Canada: Alfred Schmielewski (a.k.a Maha Yogi A. A. Narayana).
September 11-13, 1988: Edgar C. Whisenant. Or maybe it's on the 15th. Or October 3. Or maybe in 1989.
April 23, 1990: Elizabeth Clare Prophet, a.k.a. Guru Ma.
1991: Louis Farrakhan.
1992: Lori Adaile Toye and the Ascended Masters.
October 28, 1992, Korea: Bang-Ik Ha, Lee Jang Rim.
1993: Benny Hinn.
July 25, 1994: "Sister" Marie Gabriel Paprocski.
December 17, 1996: Sheldon Nidle & the Galactic Federation of Light.
March 26, 1997: Marshall Herff Applewhite and Bonnie Lu Nettles & Heaven's Gate.
October 1997, St. Louis: Kenneth Hagin.
1998: Henry R. Hall & his book.
March 31, 1998, Garland, Texas: Hon-Ming Chen, a.k.a. Chen Tau.
July, 1999: Nostradamus said that is is Doomsday.
August 11-18, 1999: Planetary flybys, "Grand Cross", Amazing Criswell....
2000: Well, you know....
March 24, 2002, Hollywood: Paul Smirnov
2004: Mike Drosnin & the Bible Code (again).
October 17, 2004: Clay Cantrell.

All of these and more in Jason Boyett, Pocket Guide to the Apocalypse (Relevant Books, 2005)