When all eleven families on Redford Crescent receive a newspaper from the middle of next week, the result is a hastily called neighborhood meeting and an assortment of get-rich-quick plans.

With eleven years of marriage behind them, Ted and Alice’s fantasies frequently start with a time machine and end with killing one or another of their spouse’s ancestors before they can procreate. So naturally, they each end up at Temponautics, Ltd. Oh, and Ted’s grandpa has some racy fantasies of his own.
In Silverberg’s Something Wild Is Loose (Vol. 3 of his collected stories), he posits that this story is “probably the most complex short story of temporal confusion” since Heinlein’s “By His Bootstraps” (1941) or “—All You Zombues—” (1959), but I would respectfully disagree. In particular, I would describe Heinlein’s two stories as the most complex short stories of temporal consistency in that there is but a single, static timeline and (in hindsight) every scene locks neatly into place within this one timeline. By contrast, Silverberg story involves multiple time travel choices by the characters in what I would call parallel universes. The confusion, such as it is, stems more from what appears to be alternate scenes in disconnected universes rather than temporal confusion per se.

Silverberg’s introduction to “Trip” in the collection Trips, vol. 4 of the Collected Stories of Robert Silverberg (Subterranean Press, 2009), states that he wrote the story with the goal of being the ultimate alternative universes story, and he lived up to that goal, devising nearly a dozen alternative Bay Area universes for his hero Cameron to express his wanderlust. Admittedly, there’s no actual time travel because the story was part of an anthology of ultimate sf, and Silverberg left the time travelin’ to Philip K. Dick’s “A Little Something for Us Tempunauts.” But there is a world that Cameron thinks is a 1950s San Francisco (it isn’t) and there’s a chance that Cameron experiences the passage of time at rates that differ from world to world.

Warning: The first publication of the story in that ultimate anthology (Final Stage: The Ultimate Science Fiction Anthology) was “cut to shreds” by a ham-handed editor at Charterhouse, so your best bet is to read it in one of Silverberg’s later collections.

You’ll enjoy this story, but I’ll give away no more beyond the quote below. By the way, if you get the original publication, you’ll also see Kurt Vonnegut and Marilyn Monroe.