Or as Nick Lane-Smith, 33, an entrepreneur and fixture at the Sub, a warehouse loft in the Mission District, put it: “You get to come home every day and it’s like opening a cereal box with a toy inside. You have no idea who’s going to be over and what they’re going to be doing and who they brought with them that you get to meet.”

If the Embassy is the Four Seasons of San Francisco’s commune scene, Langton is the hostel that took its decorating cues from the A&E show “Hoarders.” On the Thursday before Halloween, an overflowing blue Dumpster stood before a kitchen, which contained an array of potted plants amid dozens of spice bottles, a jar of Vegemite and a pumpkin.

The compound had just received a half-dozen boxes of dead animals. Mr. Partensky said the carcasses would be used to make chimeras (creatures made up of parts from different species) during a coming Halloween party, and pointed to a fetal pig with owl’s wings hovering over the garage.

The atmosphere at Langton is not usually so Dionysian. Mr. Partensky, who was born in the Soviet Union and lived in a refugee community in Italy as a child, started the space with a group that included his sister, a carpenter, and a clown because, he said, he fantasized about a place where “the distance between questions and answers would be shorter because you could walk down the hall to ask someone with that expertise.” (He’s building Sourcery, a service that helps restaurants, hospitals and other large organizations place bulk orders of food, with a former housemate.)

Since Langton opened six years ago, Mr. Partensky estimates about 1,000 short- and long-term guests have stayed there, each paying upward of $1,200 a month in rent. Unlike in the old days, lost souls can’t saunter off a Volkswagen bus and expect a bed (and a toke); Langton, the Embassy and others have rigorous application processes for prospective residents, with questions like: “If you had a superpower, what would it be?” Mr. North was interviewed by 10 of 11 prospective housemates before being accepted into the Embassy. (At some communes, friends of residents looking for a place to crash can claim a bunk in a shared room for $30 to $40 a night.)

The Sub has functioned as a communal space for decades, but in recent years it has been frequented by a techie crowd. Over vegan chili and kale salad at one of its recent monthly dinners, arranged through Facebook, Mr. Lane-Smith asked each of the nine attendees to share their name, a phrase about their day and what they were really excited about. Phrases included “heads down” from a software developer focused on producing “quantity over quality” and “serendipity” from a video game designer who bonded with her fellow Caltrain commuter riders that morning when their train was delayed by a suicide.