When He’s Coming Back:
Like everyone’s said, nobody knows.
Why Second Coming in AD 2000 Nuts Are Only Regular-Grade Nuts, Not Heavy-Duty Weirdos:
“With God, a thousand years are as one day.”
Supposed date of Creation (per “Scientific Creationists”): 4004 BC. Creation took six days. Reasonable to expect it to last six “days.”
4004 BC + 6000 years = 1996 AD, give or take.
Seven years of Great Tribulation -> 2003 AD
Christ coming halfway through it: mid-2000 AD, or right about now. [This section represents a summary of one take of conservative Christian thought on the Second Coming, and is not to be confused with the opinions of the poster, Cecil Adams and the Straight Dope, Inc., the Chicago Reader, or anybody else with the sense God gave Anser albifrons.]
How Christians Are Supposed to Prepare for the Second Coming:
>> Live each day as if He’s coming today to judge you.
>> Don’t expect him any time soon.
Why Everybody Is Wrong:
The first time around, nobody but the Jews expected a Messiah in the first place. Jewish thought was divided between those who thought there would be an actual person showing up, with the majority of these expecting a military leader, a minority expecting a perfect High Priest, and a few oddballs expecting one of each; and the “reasonable people” who explained it away as the role of the Jewish people to live the ideal life God commanded and suffer for the sins of the Gentiles, a la the Suffering Servant passages in Isaiah. Nobody expected an itinerant rabbi from East Podunk, Galilee, who would teach and heal and then die a shameful, agonizing death, and come back to life. And, effectively, nobody who knew him while he was doing all this stuff got the message, even though he’s said to have made it quite explicit in his talks with the Twelve.
Has human nature changed a whole lot? Look at what the “Christians” think about The Last Temptation of Christ and Corpus Christi? Read all 15 pages of the “Christianity and Love” threads, parts one through three. Odds are, if he shows up again, he’ll probably get zapped, and it’ll probably be the self-proclaimed religious righteous who do it.
Heck, for all anybody knows, he may be around already, doing the same deal as before where he hangs out and prepares himself until he’s adult; he may very well be spending the summer in the Ozarks with his boyfriend.