Entrepreneurs, hackers, investors and media players hung their jackets on hooks and availed themselves of booze. Brooklyn Lager and Magic Hat #9 flowed from kegs, two bartenders poured cups of red and white wine. At one point, 51 people were checked in on Foursquare.

Foursquare founder Naveen Selvadurai was there, in fact, as was Mediaite editor Rachel Sklar. Even the elusive 4chan founder Christopher Poole--his new startup Canvas is based at 113 Spring--was spotted.

The two startups had missed their shot at the holiday party season. Jumo was heads-down, fixing snags after a bumpy December launch, and GroupMe was in the enviable position of figuring out how to spend the $10.6 million they had just raised to build out their popular group text messaging and calling app. Perhaps it was those weeks at the grindstone that gave the party an air of anarchy.

Michael Galpert of Aviary was complaining about the overabundance of glass at General Assembly, the chic and secretive coworking space in Union Square. He walked smack into the glass plate front door, he told a group of founders who work out of the space, and had to get ice from Argo Tea. "Let's get vinyl letters and sticker GA on the door," someone suggested. "Or just break in at night and spray paint it."

Upbeat hip hop thumped from one side of the room while bad karaoke filled the other. "I've been told to make sure everyone is having fun," GroupMe's boy wonder developer Pat Nakajima earnestly told The Observer before he disappeared to sing. Guests took turns delivering painful versions of Journey, Barenaked Ladies and Nirvana; later, cans of Bud Light were shotgunned.

"It's like Dazed and Confused," one well-known New York venture capitalist told The Observer as he surveyed the festivities. "I get older, entrepreneurs stay the same age."

"I have a funny story about GroupMe," another local investor and entrepreneur told The Observer. Co-founder Steve Martocci once flubbed a demonstration of GroupMe's conference calling ability in front of super investors Chris Dixon and Ron Conway and pop star Will.i.am, he said. Martocci set up the call but at the moment when everyone's phone was supposed to ring, there was silence. "It was really scary, because Mike Arrington was there. Steve was melting." Finally Martocci gave up. "That's GroupMe!" he said, and walked off.

GroupMe and Jumo share the third floor of 113 Spring, also the Buzzfeed headquarters. Jumo, a social network for non-profits and do-gooders, was born after Facebook co-founder Chris Hughes worked on the Obama presidential campaign (see Fast Company's cover, "The Kid Who Made Obama President") and decided to stay in the change-the-world line of work. Hughes, impeccable and understated, worked the room, collecting compliments on his Stephen Colbert appearance the night before. The Jumo team clustered in a corner by a wall, where the company's to-do list was still spelled out in sticky notes.

GroupMe's accountant Joey Friedman was in attendance, boasting a GroupMe octothorpe on his lapel. He does business development for the Disco Biscuits--he and Martocci met at Camp Bisco 4--but he's started working with startups in the New York tech scene. "A friend told me, 'Dude, every startup I know hates their accountant!'" he said, standing outside, smiling as the tipsy startup kids smoked and shouted at each other.

ajeffries [at] observer.com | @adrjeffries