You probably have no idea who Brand New is, but this foursome from Long Island, NY has gained enough steam recently to fill the Koolhaus this past Friday and inflict several 13-year-old girls with hysteria.

It’s all partially because of the budding popularity of so-called ’emo’ (short for ’emotional’), a genre of music that’s all about the heartfelt lyrics. Emo’s sound varies wildly from acoustic to punk and Brand New tips more towards the latter. Some have dubbed them ‘heartcore’ or even ‘screamo’ (see Alexis on Fire for an example of the latter).

The show, which was moved to the larger Kool Haus from its original Opera House venue when a snowstorm cancelled the band’s scheduled December date, featured the band playing a 90-minute set of songs from both their first album Your Favorite Weapon and their 2003 release, Deja Entendu.

Prior to the show, the air was thick with anticipation, and when the band finally took the stage, the audience exploded. As they launched into my favorite track off DE, the brooding “Okay I Believe You But My Tommy Gun Don’t”, the boys looked a bit nervous and rigid. Thankfully, that did nothing to bring down the incredible energy of the crowd. The lights that swept the floor showed an enormous, seething mass of kids jumping, screaming, moshing… even bringing out a lighter or two for the tearjerkers.

By the time they launched into the YFW oldies like “Logan to Government Center” and “Soco Amaretto Lime”, the band looked more confident. Vin Accardi paced the stage, swinging his guitar dangerously and sweat rained into the air as Brian Lane beat the drums without mercy.

Any inhibitions that remained fell away as both band and crowd lost it during hard hitters “The Quiet Things That No One Ever Knows” and “Sic Transit Gloria…Glory Fades”, which rounded out the set. Even the scenesters hiding in the over-19 lounge left their cushy chairs to party on the floor.

Accardi amazed onlookers as he threw his guitar high into the air, caught it and then dove into the frenzied crowd, promptly followed by various audience members. Not to be outdone, frontman Jesse Lacey madly paced the stage, yelled at the crowd and even played a little solo cover of Coldplay’s “Yellow”.

Amidst all the guitar-heavy closing tunes was the moody and sparse opening track to DE, “Tautou”. More than anything, “Tautou” underlines Brand New’s evolution since YFW and underscores the reason they’re keeping it fresh in the face of endless emo/pop-punk clones: a darker tone with startling, vivid lyrics that bring amazing energy to their concerts and keep the kids coming back for more.