The apocalypse is upon us. Again.

“Seeking a Friend for the End of the World” is one of those tender Armageddon love stories that crop up every so often — 1988’s “Miracle Mile,” 1998’s “Last Night,” 2009’s French thriller “Happy End.” This time there’s an asteroid headed toward Earth, scheduled to smack down in a week, and in the global panic and resignation that ensue, two lost souls find each other. If that sounds like Lars von Trier’s “Melancholia” on Prozac, it is.

Somewhat improbably, the leads are played by Steve Carell and Keira Knightley — a pair of actors who go together like burgers and tea. But the two give it their all (which in Knightley’s case is occasionally too much), and before the script goes gooey on us in the back half the movie has a cracked, sardonic take on how society might confront The End.

Writer-director Lorene Scafaria imagines our final days as a party on a grandly neurotic scale, with everyone trying to cram his or her bucket list into one short week. Heroin? Adultery? Pottery classes? Why not? The only person who hasn’t found the spirit is Dodge (Carell), a sad sack insurance salesman who’s very much an extension of the star’s role in the recent “Crazy, Stupid, Love.” As in that film, his wife dumps him in the film’s opening scene, bailing out of their car on a dark suburban road. “I think we missed the exit,” Dodge says.

These early sequences are tonally rickety but inspired, exploring with light comic surrealism the human impulse to grab at experience before the lights go out. Dodge’s best friends are a pair of middle-class marrieds (Rob Corddry and Connie Britton) who feed their children martinis and start spouse-swapping with grim purpose. Air traffic grounds to a halt, cellphones fail, bodies fall from buildings. A magazine cover names Jesus Christ and Oprah as the “Best of Humanity.”