This track from the Boston-based trio Freezepop's latest album "Future Future Future Perfect" finds singer Liz Enthusiasm wondering if listeners would prefer her music if she wrote songs about "more serious things." The song alternates between defensive self-deprecation and a defiant attitude toward indie fans who reflexively dismiss peppy pop songs about fun and dancing. Of course, the acute self-awareness of the lyrics and the confrontational title of "Pop Music Is Not A Crime" immediately signal that the tune is much more than "another song about dancing," and the chilly, somewhat aloof sound of the piece suggests that the group is not quite as extroverted as they may seem in the abstract. If anything, the cut serves as a manifesto for a group who have no doubt spent much of the past decade justifying their music to uptight rock fans and have come to view their taste for cheery frivolity as a form of rebellion.

This excerpt from the hip-hop producer Aesop Rock's album-length composition "All Day" was commissioned by Nike as part of their Original Run series. The music is designed to accompany a 45 minute run and follows the arc of a good workout; it begins with a brisk but workable pace before building up to an intense crest and ending with a cool-out period. That said, you hardly need to break a sweat to enjoy Aesop Rock's mix, which ebbs and flows with a graceful internal logic that does not actually need to be paired with any specific activity. Still, it's hard to imagine sitting still while listening to this excerpt, which is timed to fall at the point in the run when you ought to be hitting your stride. The music sets into a mildly raunchy funk groove punctuated by Aesop Rock intoning the word "OK" with a calm, reassuring tone that encourages the listener to keep on doing whatever they are doing, whether it's running, dancing or organizing their receipts.

Pistol Pete's productions often seem designed to give the listener an immediate jolt of adrenaline within the first few seconds of the track. After years of releasing bootleg remixes of popular hip-hop tracks, "Make 'Em Pop" is Pete's first official release and the sound is typically frenetic and super-charged. The song sounds as though it should be the soundtrack to an action-packed chase scene, with each twist and turn amping up the stakes and bringing the audience to a new level of excitement.