Multihued lights shone and Cee Lo’s Georgia blasted from speakers in the Tabernacle, a downtown Atlanta concert hall, about as far removed from a traditional business environment as one could imagine. But there’s very little traditional about Startup Riot.

Now in its fourth year, the event brings together potential investors and 50 entrepreneurial companies looking for capital. Startup Riot allows the entrepreneurs three minutes each to pitch their companies to investors.

Nearly 500 people attended the February event, making it the largest Startup Riot yet, said founder Sanjay Parekh, EE 96. Sponsors included Georgia Tech’s Advanced Technology Development Center and the Georgia Tech Research Institute. More than a third of the entrepreneurs presenting at the event were ATDC members.

Andrew Warner, an entrepreneur whose online greeting card company Bradford & Reed grew into a $35 million business, delivered a keynote address.

Warner explained that he didn’t have any money to start his company, only an idea. When he noticed that clothing retailer J.Crew had a no-limits return policy, Warner took back every piece of J.Crew clothing he owned. His first computers came from Staples, which allowed returns as well. He would use the computers and, as soon as the return term was about to expire, take them back and replace them with new models.

“It doesn’t take money to make money,” he said. “It takes a sense of mission. When you want it, there’s always a way to get that business off the ground.”

Warner now operates Mixergy, a website that features interviews between him and fellow entrepreneurs. He offered advice based on those conversations.

He encouraged entrepreneurs to push away from their desks and focus on expanding their networks. He also stressed that starting a business inevitably includes some hard moments and being successful requires finding a way to persevere.

“It’s tough. People underestimate it going in and downplay it afterward,” Warner said.

The presentations then began in what seemed like a blend of a rock concert, speed dating event, business meeting and, on occasion, stand-up comedy show.

The entrepreneurs took different tacks to gain the attention of investors. Some were bombastic. Others were professional or demure. One engaged in an extended pretend phone conversation while wearing angel wings.

Almost all of the companies were Internet or social networking based. The entrepreneurs competed for a spot in the event, and they weren’t charged for their three minutes.

Among those pitching was Anirudh Ramachandran, a PhD candidate in the School of Computer Science at Tech. His company, Nouvou, offers data-loss prevention. While Ramachandran is comfortable doing research, making a pitch to hundreds of people was a new experience.

“The first thing you realize is that, unlike a research talk, a pitch has to be short, have a compelling hook and also be dumbed down into something any layperson would understand,” he said. “Nobody is going to buy your product if they cannot instantly get its value.”

After his three minutes, Ramachandran met with several investors to demonstrate the Nouvou system. Each entrepreneur had a booth in another room. While Ramachandran didn’t make a business deal, he was glad to have participated.

Parekh said that while it’s rare for business deals to be signed at the event, Startup Riot gives entrepreneurs the chance to meet with business leaders and receive feedback on their projects.

Investors who had been conservative during the lean economy of recent years were more active at the 2011 Startup Riot, Parekh said.

“The feel of the event was definitely more upbeat than in previous years, which I think is a reflection of an improving mood,” he said. “That said, I think there are still investors who are reeling from losses over the year while others are getting aggressive and finding opportunities to invest.”