For Adam Nelson, 26, the city of Pittsburgh is a playground.
A bush is not a bush -- it's a place to hide behind, and strangers aren't necessarily strangers -- they might be teammates.
The point in this moving game of hide and seek, Super Secret Spies, is not to be spotted as you try to make it across the city from one hideout to the next, even though you have to keep your team number exposed.
"Super Secret Spies turns the street that you walk down every day into this adventure," said Mr. Nelson, who lives in Highland Park. "All of these games do something for the players to make them see their city or other players in a very different way."
This is just one of the games played by City of Play, an organization Mr. Nelson created for adults of all ages, especially those 20 to 30, who may have forgotten how to have unstructured fun.
After working with children at summer camp four years ago, Mr. Nelson realized that he hadn't gone out to play without reason in a long time, and that bothered him. So he invented Obscure Games -- now called City of Play -- a loose organization that brings adults together to play new and innovative games without focusing on winning or losing as much as enjoying the experience.
Its last event, a 5K marathon called City Spree Race, drew 100 people and 30 volunteers. Participants created their own routes between obscure checkpoints around the city. A 70-year-old who participated in City Spree was one of the top finishers, he said.
Born in Fresno, Calif., Mr. Nelson grew up in East Stroudsburg, Monroe County, and graduated from the University of Pittsburgh with a degree in economics. He works as chief creative officer for a Web application he created called Drop Kicker. Physical therapists use it to help patients heal at home; it sends them reminders to help them to stay on track with their goals.
"What City of Play tries to do is remind adults that playing is not just a thing that kids do, it is a thing that we do all the time whether we realize it or not," Mr. Nelson said. "We really want to look at play as a tool that can be used to improve the overall quality of life in the city."
This year, Best Games Fest, headquartered Downtown in the Arcade Comedy Theater, will be held all day Aug. 31 and will take the best games from these festivals and from game designers around the country. Participants can find more information at cityofplay.org/festival.
Also at 7 p.m. Saturday, City of Play will produce two games, Poetweet and Dance Avenue, for the Three Rivers Arts Festival. Participants can create poetry on Twitter for Poetweet and dance on the sidewalk to their own music with Dance Avenue. Both games are free, but people can get tickets in advance for Dance Avenue at cityofplay.org/traf.
With the support of the Sprout Fund, City of Play is identifying, documenting and directing people to Pittsburgh Third Places or natural community gathering places for the project "We Are Here." So far, it has identified Frick Park Market in Point Breeze, 720 Music, Clothing and Cafe in Lawrenceville and Market Square in Downtown.
City of Play has game events two or three times a week. It meets at 7:30 p.m. every Wednesday at Hambone's Pub in Lawrenceville for pub games and at 3 p.m. Sundays for field games at Flagstaff Hill, Schenley Park.
To get involved, people "just need to show up," Mr. Nelson said. They can also visit cityofplay.org, follow @cityofplay on Twitter and "like" www.facebook.com/obscuregames.
When I was a kid, I used to love ... Magic tricks and quantum mechanics.
I'm surprisingly good at ... Tying knots.
My perfect weekend ... Involves brunch, games and making things.
Most mornings I get up and ... Eat eggs for breakfast. What happens afterward is different every day.
Favorite video game is ... Johann Sebastian Joust. But it's not really a video game.
Favorite board game is ... Impossible to narrow down, though I am a big fan of the games being created as part of the City of Play's Game Engine (cityofplay.org/thegameengine).
The best game I ever played ... Probably hasn't been invented yet.
Someday I'd like to ... Ride my bike across the country.
Pet peeve about Pittsburgh: Impatient drivers.
Favorite spot in the 'Burgh: The neighborhood third place: www.wearehereproject.org.
When I'm not at work, I can often be found: Sleeping.
My biggest surprise about Pittsburgh: That everything is connected to everything else.
Best advice I was ever given: Don't make art to make money. Make money so you can make more art.
Marina Weis: firstname.lastname@example.org.