Blitzen Trapper manage to have their cake and eat it too: They mine traditional pop and folk sounds for their timeless-sounding songs, yet manage to inject just enough strangeness to make their records (and shows) a joyous ride.

The Portland band played a too-brief (blame lead singer Eric Earley’s thrashed vocal cords) but enthusiastic show at Neumo’s Sunday night to a capacity audience, and I haven’t heard so many people sing along at a show in a long, long time. Tracks like “Furr,” with its memorable lyrics about a boy raised by wolves and an instantly-adhesive folky melody, turned the jaded cluster of humanity jamming the house into happy grade-schoolers.

Earley and co-singer Marty Marquis made a great team, the former’s effusive energy contrasting amusingly with the latter’s deadpan between-song patter (incidentally, Earley sounded great despite–or perhaps because of–the wear on his voice). And the entire band played tight, offering a good mix of material from all three of their full lengths. The audience lapped it all up, but the undisputed highlights from this corner were the set opener ” Sleepy Time in the Western World,” on which the band perfectly replicated the Beach Boys harmonies of the studio version and a raucous, jumping take on their most propulsive rocker, “Fire and Fast Bullets.”

Other wags have christened these guys “Americana,” but the sprinkles of odd keyboards and the tinges of strangeness in their lyrics separate them from the earnest folkies mumbling their way through college radio in these devalued times. Blessedly, they don’t take themselves too seriously. At one point, Marquis took the stage solo for a hysterical history lesson on Portland, which he capped with a sloppy-but-fun cover of Kenny Rogers’ “The Gambler.” And the audience sung along gleefully with that too.