It might very well be the single of the year. An audacious, joyous, larger-than-life pop explosion, "Sleepyhead" weaves an entrancing, Avalanches-esque spell with tromping dance beats, munchkin voices, and a backdrop of shimmering bells. Meanwhile, Michael Angelakos shrieks impressionistic lyrics over squiggly synths, sounding anything but sleepy, and the whole song feels like an instantaneous head rush stretched out to three euphoric minutes.

The new "Sleepyhead" single has been tacked onto Passion Pit's debut EP, Chunk of Change. Passion Pit is Angelakos' recording project for which he sings and plays all the parts on record, although the Cambridge, Massachusetts, act is now a five-piece band for live shows. Chunk of Change was originally recorded by Angelakos as a personal Valentine's Day gift for his girlfriend, but as friends began to hear it, he was eventually convinced to bring Passion Pit to a broader audience.

Knowing its ain't-that-sweet origins, the Chunk of Change EP is a more subdued effort than "Sleepyhead," sounding almost like gentle bedside music in comparison. But Angelakos' gift for sonic invention is apparent, especially in the rising and falling space-cricket drone of "I've Got Your Number" or the stereo-spanning synth pads of the vertigo-inducing "Smile Upon Me." Many of Passion Pit's songs sound like blasts from futures past, like those outlandishly dated sci-fi movies of the 1980s, where the brave new worlds they described have not come to pass quite as they said they would.

Conventional songcraft is on display throughout Passion Pit's limited output (a full-length record and multimedia project is in the works for next year). There's the yearning vocal above the robotic dance groove of "Smile Upon Me," and the exploration of R&B in "Cuddle Fuddle." Stevie Wonder's superstitious clavinet adds a gentle funk nuance to "Better Things," while "Live to Tell the Tale" has an almost McCartney-like approach to melody.

But it all comes down to "Sleepyhead," the kind of song that can ultimately make (and, perhaps—if the band fails to deliver upon its initial promise—break) a band. While the prospect of more music from Passion Pit is an exciting one, the buoyant, helium-headed ecstasy of "Sleepyhead" is enough for now.