Flash mobs have sung, danced, and frozen their way into popular culture over the past few years.

But on June 30 on the University of Michigan Diag in Ann Arbor, Greg Grossmeier and Carrie Ashendel held a “flash wedding.” About 35 people attended the wedding, including some passers-by.

The spontaneous wedding was born partially by design and partially by necessity. Grossmeier and Ashendel are moving at the end of the summer, and wanted to wed before leaving town. They also have both worked in the "open source" community and liked the idea of sharing their marriage with friends as well as strangers.

Open sourcing is an idea that originated in software development to allow users to share in the development of software and other products. Users of an open source product can alter the code and then share their improvements (the Mozilla Firefox Internet browser is an example of open source software).

"'Open' means being able to get that content and change it, and modify it," Grossmeier said. "Being a producer in the culture in addition to a consumer. Same with love."

With time running out before their planned move, the couple decided that expediency and the uniqueness of an “open” wedding trumped tradition.

They reached out to their online network of friends to help them plan, a technique sometimes called crowd-sourcing.

“I sent out a tweet at 9 p.m. Wednesday night asking if I had any friends who could officiate a wedding, and about 10 followers responded that they could do it,” Grossmeier said. “Around noon on Thursday (the day of the wedding), I posted on Google+ ‘Today at 4:10 pm, in front of Shapiro Library, Carrie and I will be getting (officially) married. Join us!’”

Bobby Glushko, an associate librarian at the University of Michigan copyright office, officiated the wedding. Grossmeier’s use of social media to plan the event was unlike anything Glushko had seen before.

“It was kind of funny that even though I can see Greg from my desk, I found out about the wedding on Twitter,” Glushko said last week.

Ashendel also used online tools to communicate with her fiancee in the hours before the wedding.

“At first I just thought it was going to happen in the break room at Greg’s work,” she said. “When I found out we were going to do it outside, I got ahold of Greg on IM and was like, ‘Can I invite my mom?’”

Ashendel’s mother did attend the ceremony and helped make it a bit more formal, providing a table, a cake and some sparkling pomegranate juice in place of Champagne (alcohol is not allowed on campus).

Grossmeier, who works for Open.Michigan, the university's initiative to encourage online sharing of research, teaching materials and ideas, said that the wedding was emblematic of their personalities.

“Whatever we create, we always share with others no matter what it is,” he said. “Whether it’s our blogs or our love, it’s all the same realm.”

Ben Freed is a summer intern at AnnArbor.com. You can reach him by email at benfreed@annarbor.com or by phone at (734)-623-4674. Follow him on Twitter @BFreedInA2.