These 20-somethings have built a wildly successful business based on nostalgia for the early 2000s - and New Yorkers can't get enough

Ethan Maccoby and Alex Badanes don't actually share any family ties, but you could easily describe them as brothers. The two grew up together as neighbors outside of London and have been best friends ever since.

Their strongest tie is - and always was - music. Their Friday night hangouts started in their parents' basements during their teen years, and routinely included listening to "emo" music from popular bands like Yellowcard, Taking Back Sunday, and Brand New.

"Growing up, our favorite thing to do on a Friday night was blast emo and rock out together," Badanes told Business Insider.

Their hangout ritual hasn't changed much, except that they're now selling out 1,000-plus-occupancy venues to blast the exact same early-2000s songs for fellow fans who also feel nostalgic for their youth.

The two's enterprise, called "Emo Night Brooklyn," has since graced seven different venues, with ticket sales growing in volume with each event. Ahead, take a look inside a recent rowdy event (held at Irving Plaza in Manhattan) and learn the story behind their growing business.