A brief timeline: in 2010, a couple of retro-sassy Berklee grads, Nick Noonan and Amy Heidemann, a/k/a Karmin, cover a few pop songs and slap 'em up on YouTube. Heidemann flaunts a mind-blasting ability to rock the mike when she rips through Busta Rhymes's rapid-fire rap in Chris Brown's "Look at Me Now." The video explodes and sends ripples across the Interwebz, garnering 16 million views. Before long, they're performing on Ellen and Saturday Night Live, gabbing with Ryan Seacrest, and jamming with Questlove. Their debut album drops late this spring. We're pretty sure there's gonna be plenty more social-media mania before this duo's happy ending.