The Bobs, that ever-clever foursome of alternative a cappella singers, performed a perky concert Saturday at the Maine Center for the Arts. Popping up regularly in the state for the last 10 years or so, the Bobs have gathered a local audience of rowdy fans who like the quirky harmonies and even quirkier lyrics of this funky quartet.

And what’s not to like? The Bobs take unabashed delight in any type of humorous quackery they can work into a few existential words and musical notes. Take, for instance, the song “Elwood Decker,” a vocal eulogy lifted from an obituary that bassman Richard Bob Greene read in a newspaper one day. (Every group member takes Bob as a middle name, by the way). For 88 years, Elwood Decker walked on the railroad tracks and “the other day he was abstractly struck by a train…now he’s gone…and there’s no more to tell.” Pretty uneventful plot line, but combine it with exotic vocalizations, and you’ve got the Bobs’ version of a richly harmonic universe filled with little stories and big sounds.

The real adventure spirit of this group comes from having no instrumental accompaniment yet still providing the sounds of, say, a horn or a xylophone. Joe Bob Finetti alone psychotically furnishes the brass section, the percussion section and the vocal pedal steel guitar (which he played with hilarious success in “Mess Me Up Again” — another Greene original). Perhaps Joe Bob’s most unforgettable moment, however, came about when he dropped to his haunches for the wind-out guitar solo (a la Jimi Hendrix) in a cut-loose performance of “Purple Haze.”

Although a Bobs concert is certifiably loony, it isn’t always over the top (as was a Gregorian chant version of “Light My Fire”). “Particle Man,” featuring Joe Bob in the boyish lead vocals, showed off traditional urban-street harmonies. Several “instrumental” jazzy jams were unsurpassably thick with texture, thanks also to founding Bob and all-around nice guy, Matthew Bob Skull, and newest Bobs member, Lori Bob Rivera (whose voice rivals a diamond’s ruggedness and clarity). Other cover songs included the Coasters hit “Searchin’,” “Unchain My Heart,” “Ain’t Nobody Here But Us Chickens,” “Caravan” (done by the Mills Brothers in the 1920s) and “Helter Skelter.” In an encore, the group snapped its way through a zingy version of “Cowboy Lips,” one of their signature goofy pieces.

Since their debut in 1981, the Bobs have risen to a cappella fame, which seems to have given them a cynical cockiness that falls short of their vocal accomplishments. In Orono, they poked fun at the crowd, shamelessly promoted their sale table in the lobby, and guilelessly admitted to working out new numbers on the Maine crowd. That doesn’t say much for their professional manners — though you’d be hard-pressed to find much that was unpalatable in their superb music.