According to The Nice and Accurate Prophecies of Agnes Nutter, Witch (the world's only completely accurate book of prophecies, written in 1655, before she exploded), the world will end on a Saturday. Next Saturday, in fact. Just before dinner.

So the armies of Good and Evil are amassing, Atlantis is rising, frogs are falling, tempers are flaring. Everything appears to be going according to Divine Plan. Except a somewhat fussy angel and a fast-living demon—both of whom have lived amongst Earth's mortals since The Beginning and have grown rather fond of the lifestyle—are not actually looking forward to the coming Rapture.

And someone seems to have misplaced the Antichrist . . .

Amazon.com Review
Pratchett (of Discworld fame) and Gaiman (of Sandman fame) may seem an unlikely combination, but the topic (Armageddon) of this fast-paced novel is old hat to both. Pratchett's wackiness collaborates with Gaiman's morbid humor; the result is a humanist delight to be savored and reread again and again. You see, there was a bit of a mixup when the Antichrist was born, due in part to the machinations of Crowley, who did not so much fall as saunter downwards, and in part to the mysterious ways as manifested in the form of a part-time rare book dealer, an angel named Aziraphale. Like top agents everywhere, they've long had more in common with each other than the sides they represent, or the conflict they are nominally engaged in. The only person who knows how it will all end is Agnes Nutter, a witch whose prophecies all come true, if one can only manage to decipher them. The minor characters along the way (Famine makes an appearance as diet crazes, no-calorie food and anorexia epidemics) are as much fun as the story as a whole, which adds up to one of those rare books which is enormous fun to read the first time, and the second time, and the third time...