This Brooklyn duo are one of the perkiest bands in indie rock, routinely whipping crowds into a crazy-dancing frenzy with their cheerfully spry keyboard-and-drums tunes. On their third album, simplicity is key: Most songs are built around simple synth riffs, battered by booming percussion and topped by Matt Johnson's adenoidal voice. But Matt and Kim still cover a lot of ground, feinting at techno on the jittery "Block After Block," creating a sweeping orchestral sound on "Northeast." The album's best asset might be its pervasive optimism. "I hear that shoestrings tend to break/But they tie back together great," Johnson sings on "Where You're Coming From." Call it therapy you can spaz out to.

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“I'm Yours”

Jason Mraz re-emerged after his disappointing second album with this lead single, a Jack Johnson-esque ditty about giving yourself fully to someone else. The success of the reggae-tinged song (it earned two Grammy nods and a spot on the Billboard singles chart for well over a year) was something the folk-pop singer never predicted when he wrote it in 15 minutes at home. "I played a happy-hippie chord progression that would probably work without 50 different Bob Marley songs," he told Rolling Stone. "I thought, 'It's too novelty. This is a nursery rhyme,'" concluding that "you can never guess what's gonna be a hit."