Park(ing) Day famously helped people all over the world re-envision the lowly parking spot, encouraging DIY urbanists for one day each fall to transform these spaces in their cities into parks, playgrounds, pop-up cafés – anything other than their intended use. The original idea, dreamed up by San Francisco-based urban design studio Rebar, went on to become a model urban prototype. The city of San Francisco adopted the concept for its “parklet” program. And now officially sanctioned parklets are popping up everywhere, most recently 2,000 miles away in Chicago.

The evolution of the parklet suggests that fly-by-night urban interventions can lead to something much more permanent. And this is the idea behind a series of “urban prototyping” festivals created by the Gray Area Foundation for the Arts in San Francisco. “We’re working with lessons learned form the parklet and Rebar and others to inform how projects that start at the small experimental prototyping scale can grow and expand across neighborhoods and cities,” says Jake Levitas, research director at GAFFTA.

The foundation held an “urban prototyping” festival in June in Singapore. Now it’s bringing the public showcase to downtown San Francisco in October, when the next generation of parklet-like ideas will be on display for a weekend. GAFFTA and several partner organizations – including the Mayor’s Office of Civic Innovation, the Intersection for the Arts and 5M Project – have been looking for replicable, affordable ideas at the intersection of public space and technology.

“We don’t want $50,000, $100,000 really nice installations necessarily,” Levitas says. Rather, the groups want to showcase the kind of open-source idea that could be demoed in San Francisco and rebuilt around the world, just as parklets were. Each project, they hope, will have a technological component, whether that involves sensors, smart phone apps, web maps or digital how-to guides for reconstructing the ideas. Last month, the festival released an open-source call for prototypes. Over the weekend, it settled on 18 whimsical, utilitarian, futuristic and quirky ideas for our city streets. Each will be on display Oct. 20-21 on a two-block stretch of San Francisco, alongside another five-to-ten ideas Levitas is hoping will come out of a “makeathon” next month.

“We seem to have hit a vein of some sort in the community here,” Levitas says. He was hoping for a few dozen proposals (each winning entry got up to $1,000 to build its idea). The festival got about 90, many from outside of San Francisco.

You can peruse all of the winning projects here, including a mobile app that will turn objects in the city into a digital typeface, and a number of ideas for transforming ugly urban fences into edible and auditory pedestrian experiences. But we wanted to highlight some of our favorites as a first peek at the fall festival, and at what may be the next great – even better – Park(ing) Day ideas.

The DIY Traffic Counter

This idea will really appeal to the urban geek/amateur researcher. For $80, you can assemble your own kit based on this prototype, roll out your own unobtrusive sensor across a street and collect traffic-count data for passing bikes or vehicles. The data can also be uploaded into a central database to share with others. That information, in turn, could help you state your case as you lobby for changes and improvements to city streets, to accommodate, for instance, more bikes and fewer cars.

Darkness Map

via DarknessMap.com

This smart phone app collects data on the brightness of city streets as you shoot geo-tagged video walking down the block. The data is analyzed algorithmically “to generate the average brightness of each frame.” And that information can then be mapped onto the street, as with the above image. Such maps of the city could be cross-referenced with different indicators of light-dependent urban activity, such as crime, graffiti and traffic accidents.

CLIP + SLIDE

This one might be our favorite, although it won’t particularly aid anyone’s urban research or policy planning. This prototype could turn any set of public stairs into a xylophone with clip-on keys. We’re picturing that great FAO Schwartz scene from Big – except you ride down it like a slide. The notes could be rearranged to play different songs, and you could also share your favorite compositions with an online song book. Urbanists are always talking about how to activate public spaces. We imagine this will do the trick.

The 10-Mile Garden

You’re not allowed to park in front of a fire hydrant. But that doesn’t mean you can plant a garden there. Add up all of this fire-hydrant-fronted space in San Francisco, and it would be the equivalent of a new 10-mile garden in the city.

The PPPlanter

Yes, that man is standing at a urinal. This reconfigurable public urinal and sink includes biofilters to treat wastewater. We might have to see this prototype in person to believe it (though it also rings a bell). But we’re excited about the dual function it could serve during the San Francisco festival.

Pulse of the City

Literally, this prototype wants to take your pulse, from small boxes containing pulse counters that would be mounted to traffic lights or other poles on street corners. Imagine stopping at a red light, briefly touching the box, and learning that your heart is pounding at 60 beats per minute. Now that you’re thinking about this topic, Pulse of the City has “the goal of encouraging a constructive dialogue on how to design the healthier and more livable cities of the future.”

A similar idea, called Street Sensing, will use light-pole-mounted sensing platforms to collect real-time information on local air quality.