Australia's Cat Empire, or the Empire as they're affectionately nicknamed in Oz and by their exploding international fanbase, effect one of the finest marriages of sophisticated, genre-defying songcraft and party music since the Radiators basically patented the shit three decades ago.

They have themselves nailed, too, self-described as being "where the hip-hop community dances to Gypsy, the jazz purists jump to hip-hop, the Latinos bop to reggae, the Rastas shake to Latin, the elderly sweat to funk, the youth swing to dancehall, and everyone wakes up a little happier." A far-reaching collective they are, with tall promises, and all of them met. You go for the party and the impossibly digestible sounds, reggae-rock at foundation, and you leave nourished.

This was my second go-round with the sextet in 2005, and the second time isn't quite as delectable as the first — you get many of the same tricks and there's a faint whiff of predictability in how the songs unfold. But let's face it, there's an appalling lack of new bands into whose shows you just "hafta go see 'em now now now" shoehorn your friends without any sort of qualifier ("They're heady, but you'll like 'em," "Keep an open mind," "They're great if you're wide awake," "Do you like ambient music?" "They're an acquired taste," and "They're kinda like Radiohead or a more psychedelic Wilco" are harder and harder sells for this scribe, how 'bout you?). You don't have to ease into this, which is not to be confused with mindlessness, just that your affection for the group comes as easily and tastily as its tunes and long-on-ideas-short-on-blather jamming preferences are proffered.

This night's half-capacity Cambridge date wasn't quite so easy a sell: a rainy Monday night at the end of a long weekend, and because of it, not nearly as energetic or bust-out a crowd as their beyond-packed gig at the more intimate Paradise Lounge back in June. The band leaned on its recent release, "Two Shoes," flush with party rockers ("Party Started") and melodic bounce stuff, good-times invocations ("Sly," "In My Pocket"), and steering occasionally into thicker-cut jazz funk ("Protons, Neurons, Electrons").

There's an easy familiarity, key to how inviting it is: Sublime, for instance (on the Empire's "Hello"), but not so gooey-eyed and lot more energetic; or Craig Honeycutt's long-lost groove machine e:verything, or, when the sound is fully furious, the heft of a P-Funk or any of James Brown's legendary, busty rhythm sections. And those are just a few reference points; rollicking ska and a live, experimentalist hip-hop sensibility a la the Roots are also there.

The songs are elastic—drummer Will Hull-Brown and bassist Ryan Monro keep the pockets thick and juicy—and the band knows how to color them, deferring often to keyboardist Ollie McGill for electric piano and melodica injections or to vocalist Harry Angus for snappy, extroverted blasts of trumpet. These two together own a lot of the Empire's jam space; McGill with a more nuanced, let-it-come approach and Angus more a take-charge type of soloist, with loud, sparky runs reminiscent of Arturo Sandoval.

Interestingly, there's no go-to lead instrument—a guitar is only an ancillary component—and the dominant element is often percussion, supplied amply by the drums, vocalist Felix Riebl, who uses a percussion rack, and by sixth man Jamshid "Jumps" Khadiwala, who mans a set of occasionally essential, occasionally superfluous turntables on stage left.

"Two Shoes" is a slicker, somewhat less oomph-laden effort than the band's eponymous debut, so whether they'll continue to be able to write songs that have similar staying power is a concern as their star rises. They've yet to write anything, for example, that's as much of a frisson-stoker as their fan-beloved, Riebl-penned showpiece, "The Chariot," sung like a rhythmic folk-chant and building to the point where it becomes a blistering, fraternal rave-up. But give it time, and while you're waiting for the tunes to catch up to the fun, find 10 friends and go to a show.