Artist-run spaces are nothing new, though their popularity has seen a spike in the last six months to such an extent that they have become part of the mainstream art scenes in many cities. Here are a few gems that are changing the way we think about the future of exhibition spaces.

New York City: Piggybacking on the phenomenal real estate collapse in the city, a number of entrepreneuring artists have taken to occupying vacant commercial spaces for a period of time mutually agreed upon with landlords who realize the advantages of partnering with creative types (see The Warhol Economy). One of the more innovative of these endeavors is the simply-titled Exhibition, which, under the supervision of the five friends who started it  -- Elena Bajo, Eric Anglès, Jakob Schillinger, Nathalie Anglès and Warren Neidich -- has taken up residency at 211 Elizabeth Street in posh NoLita after a friend in real estate brokered the six-month use of the lobby of a luxury condo. The overarching concept of immateriality is a governing principle; shows are typically short-most last two days-during which time invited artists work in the space, either utilizing or discarding what was left by the prior exhibitor.

: The Philadelphia Institute for Advanced Studies, a studio warehouse compound in a grimy section of Kensington managed and run by artists, has long served as an unofficial outpost for some of the more creative DIY activity in the city; the month of July will see the entire building transformed by the residents into Pifas Place, a (mal)functioning city in which studios will serve functions ranging from a tattoo parlor to a temple to an observatory. Various events throughout the month will offer standup comedy as well as animation screenings and other performances. During the rest of the year the building is host to concerts, slide lectures, life-drawing classes and other types of arty loitering.

Chicago: Harley Young started KnockKnock Gallery a little over a year ago, basing his space on other alternative venues in Chi-town like Artledge and Old Gold, while converting otherwise superfluous, unusable space into a slightly awkward and very unique gallery space. The staircase and a tiny, windowless closet that constitute part of the apartment Young shares with two other people serve as the site for installations often created specifically for the venue. Some particularly dynamic uses of the space have taken advantage of the attached domestic sphere; for their show last June, The Baby, Matthew Nicholas and Eric Warner closed off the official gallery area and ran a live feed from the stairwell that broadcast their performance onto a television into the living room. Knock Knock also plays host to such popular local series as Supper Sessions, a roving slide-lecture-cum-potluck. While Young, a recent graduate of the School of the Art Institute of Chicago, has a pool of talented friends from which to cull artists, he says he doesn't serve as curator as much as he simply allows the gallery to run itself as a project space.

 Los Angeles: Eve Fowler and Lucas Michael grew frustrated that a number of their artist friends making work didn't have enough opportunities to show it. As a result, they now run Artist Curated Projects (ACP), which is based in Fowler's house but also has found incarnations in a foreclosed home and under the roofs of other artists. With an eye towards exhibiting underrepresented members of the community, Fowler and Michael began to invite more established friends to curate, requesting that the group of included exhibitors be comprised of lesser-knowns in addition to those already represented by galleries. Fowler opens her entire living space to these events, which lie somewhere between opening, community meeting and party; some of the events have featured artists making pieces in progress and inviting attendees to lend a hand. Fowler and Michael have specified they were seeking to create something that did not follow the aesthetic of a white cube; fittingly, Elie Murphy's recent endeavor with Rico Gatson included a set of beaded curtains made by Murphy that exactly fit a pair of archways in Fowler's home.

[Installation view of Rico Gatson and Elie Murphy's Pac Man installation made of beaded curtains at Artist Curated Projects; Tim Ridlin's I Don't Want to Be a Rude Boy, installation view, KnockKnock gallery, Chicago]