Last weekend nearly 100 hackathons and related events were held around the U.S. as part of the first-ever National Day of Civic Hacking -- an opportunity to spur creativity and collaboration for using public data to help solve challenges for communities, cities, states and the nation.

The Denver event, Hack4Colorado, attracted 270 attendees, including 170 hackers who were competing for a total of nearly $20,000 in prize money. Brian Gryth, founder of Open Colorado (a volunteer- run repository for government data for that state), likened the hackathon to a "digital barn raising."

"We're all pulling together here to build anything that people can use to use data to make smarter decisions," he said. "It could be a mobile or web app, a visualization or data dashboard, or other tool or service."

What happens at a civic hackathon? On Friday, the opening night, attendees mingled in a reception followed by several presentations from various leaders in the local tech and business community as well as state government officials, showing how hackers can help solve problems with public data. This included explorations of some of the data sets and developer tools (such as for Esri's ArcGIS mapping suite), as well as hacking skills and strategies.

Then, hackers and other attendees pitched project ideas along five tracks: tourism, health, sustainability, education, and government. Ideas ranged from ideas to connect veterans with jobs, to a game-like zombie apocalypse approach to emergency preparedness, and more. In all, 18 hack teams coalesced and worked over the weekend.

The best in show prize went to DeVice Colorado. This team prototyped a web app to help people find ways to feed their vices safely. "Vices" include craft coffee and beer, newly-legalized recreational marijuana, and even outdoor recreation such as hiking (a rampant addiction in Colorado). Vice-seekers can find nearby places to feed their vices, as well as safe transportation options such as bike shares and a "call me a cab" button.

…What, you don't think that sounds very civic? It just sounds like people having fun? That's the point -- letting hackers have fun putting public data to work. Because too often accessing public data is anything but fun. Just-for-fun projects tend to be creative an innovative in ways that end up benefitting more serious projects later on; this time with the added benefit of acquainting hackers with important public datasets about local businesses and resources. Also, arguably, DeVice Colorado's cab-calling button serves a civic (public safety) function.

Kristin Russell, Chief Information Officer for the State of Colorado, noted that state governments need to understand better which kinds of data citizens actually find interesting, in order to work to make all government data more interesting and useful. "When we assessed which state data sets got the most use in Colorado, we were all surprised to find that black bear sightings was #1 on the list."

Russell said that Colorado is planning to make it possible for citizens and other hackers to rate and comment on public data sets, both online and via social media, in order to assess how to improve that data or its presentation. This also can help build support within government for open data initiatives. "For instance, if you can show that a million people care about transportation information, that's very valuable for making a transportation program or project happen," she said.

Meanwhile, in Chicago, more than 60 people attended Hack for Chicago on Saturday. KDMC's Michele McLellan attended this event and said the meetup reflected the city's very active open government community. Miranda Mulligan, chief of the Knight News Innovation Lab at Northwestern University, set the stage for the day with a 90-minute exercise on app design.

This wasn't just a geek-fest. McLellan reports that Mulligan led participants through a process designed to help them gain empathy for the potential user of the app. After pairing people, Mulligan emphasized that the goal was to gain empathy for their partners as a way of developing a useful app to solve a given problem. Participants developed plans for apps that included one to help find affordable housing, another to plot bike routes, and one to find affordable parking downtown.

In Washington D.C., federal agencies and national organizations teamed up with local hackers to put federal data sets to work. Also, several federal agencies and organizations -- from NASA to the National Endowment for the Arts to the ACLU -- sponsored challenges to spur creativity and solve problems with civic data.

Civic hacking is not just about computers. The St. Louis Business Journal reported that the winning team at the St. Louis civic hackathon proposed a phone-based system to let local homeless shelters better coordinate their available space, and also to let homeless people quickly find an available bed for the night. An impromptu but valuable advisor to this project was a janitor in the building where the hackathon was held: he volunteered after his shift to explain to the hackers the process a homeless person in that city usually goes through to find a shelter spot.

In South Carolina, four complementary events (a hackathon, designathon, Mini Maker Faire and technology teaching sessions) brought together experts, resources, talent, and citizens for learning and brainstorming as well as coding. In Portland, Maine, a team collaborated to create a prototype hardware device, The Buttler, to help solve the problem of cigarette butt litter.

Also this weekend, Code for Sacramento created this video to explain the value of civic hacking:

Code for Sacramento: How Civic Hacking Helps Our Cities from Code for Sac on Vimeo.

As with the overall Open Government movement, civic hacking is growing, especially at the state and local level. One of the best resources to connect with civic hackers near you is Code for America, which has brigades and events in many cities.