In a New Mexico desert famed for its relentlessly horizontal landscape, a 15-foot monolith juts up from the ground. At its center is a three-drawer filing cabinet that contains several magazines, a “snack bar,” and a card catalog. This is no mirage or alien relic. It’s the work of Rebar, a San Francisco design collective known for mounting installations that explore the overlaps between public and private space.

The group was born in 2003, when Matthew Passmore read about Cabinet magazine purchasing a half acre for $300 on eBay as an exercise in exploring the value of land. Passmore rallied a few artist friends—John Bela, Jed Olson, and Judson Holt—and proposed building a kind of “library” on the property. “Here’s a piece of land that’s not valued in the traditional economic system,” Bela says. “By bringing art, we altered [that].”

Passmore, Bela, and crew applied the same principles to their 2005 PARKing project. Snagging a high-demand spot on a downtown San Francisco street, the artists fed its meter long enough to lay down a sod lawn and install a park bench—transforming one small piece of the urban grid into an idyllic resting place (at least until the time ran out). After receiving a mountain of emails requesting information about the installation, the team put together a how-to manual for those wanting to reenact it. Plans are in the works to replicate PARKing in Louisiana, New York, and Virginia.

Next up: the Commonspace project, for which Rebar will organize spontaneous gatherings—a tai chi class, acrobatics, singing lessons—within the publicly designated boundaries of privately owned office buildings in downtown San Francisco. “There’s definitely an impish part to this, where we’re inviting a reaction from the landlord,” Passmore admits. “But it’s really more to raise public awareness about these spaces.” After being featured on the cover of a San Francisco alternative weekly, however, such awareness may work against the collective, turning Rebar’s sit-ins into standing room-only affairs.