Sleeper Agent, 'That's My Baby' (Interface)

Bowling Green, Ky. band Sleeper Agent started out as a duo in 2008, but it wasn't until guitarist/singer Tony Smith and drummer Justin Wilson recruited 16-year-old Alex Kandel to play bass that the band really began to take off. Though Kandel didn't work out as a bass player -- her hands were too small -- her Karen O-inspired vocals turned out to be the perfect compliment to Smith's laid back drawl, imbuing the band with a sound equivalent to a punk rock version of the XX.

"You have this one window, and this is something that I'm really passionate about and I wanted to do it. I couldn't imagine not doing it and living with that. It was total instinct." -- Singer Alex Kandel