In 2005, San Francisco-based art and design studio Rebar took it upon themselves to seize a parking space, roll sod out over the pavement, and install a bench and a tree. In the two hours the installation stayed there (the length of time they could legally keep the meter fed), they had launched the first ever Park(ing) Day, a milestone in DIY urbanism that has since evolved and spread to more than 150 cities worldwide.

Around the world, these cities continue to observe Park(ing) Day in the form that best suits them. In New York last year, for example, the city's Department of Consumer Affairs offered businesses permits to extend their outdoor café seating beyond the sidewalk and onto the street, providing guidelines for seating and accessibility. And just last week, Chicago joined the ranks with its first "people spot" in its North Side Andersonville neighborhood, outfitted with seating, an herb garden, and a small hill.

That moment in modern guerilla urbanism (which began in San Francisco when Rebar realized a full 25 percent of the city's public space was devoted to cars), is one of the highlights of "Spontaneous Interventions: Design Actions for the Common Good," the American Pavilion's inherently political theme at this year's Venice Architecture Biennale. There will be no headlining starchitects or grandiose buildings. Instead, this year's pavilion presents this event and others like it, not as acts of whimsy, but rather as actions that address larger social issues.

"In a subtle way, every project we're showing is a form of protest," curator Cathy Lang Ho told ARTINFO. "What's so great about Park(ing) Day is that it says we give too much space to the cars, privileging one set of citizens over another." What Ho describes as "getting rid of excess asphalt" was an act of reclamation by citizens for their public space, one that made institutional inroads worldwide.

In a conversation with ARTINFO, Ho discussed why this year’s pavilion is more politicized than ever before, and gave us her take on what "Common Good" actually means.

There's a very diverse set of participants featured in this year's pavilion. You've got guerilla bike lanes, smartphone applications that monitor carbon monoxide, and an outdoor beer garden. What were the selection criteria?

Honestly, our criterion for projects was kind of straightforward. We were looking for projects that were initiated by the designers themselves. A lot of designers have a lot of ideas. That’s their job — to see problems by being good observers and researchers. And every architect you ever meet has a great theoretical project sitting in a drawer someplace, but getting it off the drawing board, the act of acting, is something we're using the show to commend.

In the recession, it's hard for anybody to find meaningful work, but if you're a talented person, you're not really waiting around for a client or a developer or a city planner to ask you to do something. If you're an engaged citizen, you're looking around saying, "These are the problems I see around me — in my neighborhood, on my block, in my city."

Aside from a sharp economic downturn, are there other factors fueling this DIY movement?

There's a whole confluence of factors. I think that in economic downtimes, you always see a resurgence of more heightened political and social engagement. We wrote this application in March last year, way before the Arab Spring or Occupy Wall Street happened. All this started percolating afterwards, and it was very gratifying for us. A lot of the language definitely resonates with what we're saying.

Occupy Wall Street had all these associations reminding us what the first purpose of public space is; the easy way of thinking about public space is that it’s a nice place to have a cappuccino, but really the original idea was to have a place for citizens to come together and debate issues, and for democracy to play itself out.

There's also crowdsourcing on all levels, and social networking connecting people. Online tools are facilitating a big part of this movement, linking together tribes and forging communities that you wouldn’t have been able to do before. You wouldn't have the ability to have pop-ups be a viable business model without this trend.

Has there ever been a moment in history when things were this temporary?

In the '60s people were very interested in temporariness. The way traditional urban planning has always happened has been long-range plans that looked ahead 15 to 20 years, but there were always tactics that were enacted quickly to solve problems that also had long-term benefits. 

We actually have a lot in common with the '60s and '70s, with their economic tumult and interest in guerilla-style DIY and sustainability. What, if anything, makes our generation's actions unique?

That’s a really good question. What’s new about guerilla gardens? Those have been around for 30 years. What’s new and interesting about what we’re doing? By linking all these things together we’re kind of identifying this movement. Is counterculture getting mainstream? I would think that back then, everything was at its more raw state. The guerilla gardens of the '70s were anonymous for fear of getting arrested. Now there’s a Guerillagarden.com where you can find them listed.

What has happened in the American city in the last 40 or 50 years? What processes were at work that are proving to be such an invitation for people to intervene? If people needs were being taken care of, you wouldn’t see the need for people to act on issues themselves. Cities have never been more broke than they are today. There's a general disinvestment for a lot of reasons: the decline of brick and mortar retail, the way people move through cities, the way they consume things. There are lots of reasons states are broke, but Amazon.com can't be helping them. They don't pay state sales tax! States can't invest in their own infrastructures, which leads to crumbling neighborhoods and spaces where intervention is necessary. There's also this building consciousness. You could say it’s the same reason there are so many farmers markets than ever before.

In May, curator David Chipperfield announced that the Venice Biennale's theme would be "Common Ground," which refers to both architects' shared intellectual history, and their use of shared spaces. How did that evolve for the U.S. Pavilion into the “Common Good?”

I think “common ground” is a nice term. It has nice different levels of meaning, including the literal common ground — the spaces we share. But we actually did our application in March last year, which was way in advance, before David Chipperfield got named as the director. So actually, it was just kind of luck.

In previous biennales, in 2008, and 2006, too, it was focusing on more formal aspects of what’s going on in architecture. You would kind of expect that in 2012, people would be looking more forward. After the financial crisis and all that stuff, I don’t think you’ll see very many of the other countries, if any, doing anything very flashy like fancy architecture by fancy architects. You'll find them having a kind of socially engaged theme. I wasn’t super surprised, since it's coming from Chipperfield —  he's really a thoughtful guy, as you can tell.

Does the phrase “Common Good” immediately attach an agenda to this show? And who decides what the common good is?

We’re aware that the phrase can be contested. We say “common good” in the context of people’s everyday needs, and yes it has a perspective. What is the common good? What's good for some people might not be good for other people. You might like bike lanes, but what about the rest of New York? Are bikes superior to cars? Yes, they’re less pollutive, and yes, less dangerous. Yes we think bikes are better than not having bikes!

We have a point of view, and it’s a liberal point of view, of course. It is political. The right to the city is political. Who has the power, and how is power expressed in our physical environment?

To see more projects from the Venice Architecture Biennale’s American Pavilion, on view August 29 through November 25, click the slide show. Park(ing) Day falls on Friday, September 21 this year.