One of the most acclaimed and celebrated Puerto Rican groups of the last decade, Plena Libre are proud exponents of the genre known as the "plena" -- a rhythmic folk dance thought to have emerged from the sugar-growing southern coasts of early 1920s Ponce. However, to the uninitiated listener who's willing to forego any contextual analysis, Plena Libre's Grammy-winning take on the genre might seem like an infectiously zealous strain of salsa. Their tenth album (its title translates as "enjoying, having fun") is a riotous party indeed -- a hyper-rhythmic orgy of throbbing congas/panderos, percussive shuffles, hopping piano lines, joyous vocal harmonies and parping horns.

While I'm currently gawping at a computer screen in a dimly-lit room, Plena Libre's presence in my headphones makes everything spring to life. Suddenly, the Windows start bar seems like a cluster of multi-colored balloons in the corner of the screen, and the MSN Messenger icon's head appears to be bobbing, while the stick-thin letter "I" that passes for a cursor is dancing all over the screen (that one may be my fault). With Plena Libre in my ears, this piece-of-shit laptop screen has become a unifyingly celebratory multi-colored fiesta. For added effect, I quickly erect a small, make-believe favela using empty cigarette packets for guagua and folded press releases for paradores, while an empty coffee cup is all I have to recreate Ponce's infamous Parque de Bombas.

As I glance at my "work" and decide to stop pissing about, "Juan Jose" closes on a brilliantly arresting soneo -- a stop-start breakdown of call-and-response interpolation between vocals and instruments. Elsewhere, Gary Núñez's arrangements of these original plena compositions is utterly inspired. "Olvidalo"'s toe-tapping big-band / multi-vocal harmonic jaunt, for example, and the soaring, epic treatments of centerpiece "Tributo A 'Rafael Cortijo Y Su Combo'" veritably scream musicianly joie de vivre. The album's back cover features a dedication from Núñez: "Our commitment to our people and music is unshakeable." On this evidence alone, doubting him would be madness.