It was monkey business as usual for the Barenaked Ladies on Tuesday night in San Francisco.

The five-piece Canadian troupe clowned around, basically, from start to finish during its two-hour show at the Bill Graham Civic Auditorium. The group made the crowd laugh with funny stories, clever improvisation, goofy antics and quirky song lyrics.

The thing that separates the Barenaked Ladies from other comedy-rich acts _ such as Tenacious D, which played at the same venue one week earlier _ is that this group doesn’t need humor to put on an enjoyable concert.

These Canucks could leave all the jokes behind and still have everything required to accomplish that task _ smart lyrics, catchy melodies, outstanding musicianship, great vocals and dynamic stage presence. Of course, that’s a hypothesis that will likely never be tested, since the Barenaked Ladies will probably never put on a wholly straight-laced show.

And, to be honest, nobody would want them to try.

With humor included on the laundry list of things the band has going for it, the Barenaked Ladies were able to deliver a thoroughly entertaining concert for local fans.

Before the headliners took the stage, however, Mike Doughty got the ball rolling in the right direction with an opening set that was full of great songs from throughout his career.

The singer-songwriter-guitarist began with a nod to his former band, avant-garde rockers Soul Coughing, by playing a funky version of “St. Louise is Listening” (from the group’s final studio record, 1998’s “El Oso”). He continued with solid takes on “Tremendous Brunettes” and “Busting Up a Starbucks” (both of which can be found on his most recent solo outing, 2005’s “Haughty Melodic,” released on Dave Matthews’ ATO label).

In all, the 36-year-old’s offering was the perfect complement to the one the Barenaked Ladies would later deliver.

Doughty also fills his sets with bits of humor, although to a lesser extent than BNL. His tunes are catchy enough to appeal to the headliner’s fans, but there’s a certain New York hipster feel to his music that is vastly different than the wacky Canadian vibe that the Ladies have going on.

That vibe has certainly worked for BNL over the years _ but it’s not working quite so well for the band these days. Just two years ago, the Ladies were able to headline the 22,000-capacity Shoreline Amphitheatre in Mountain View. This time around, the group was only able to draw a few thousand to a half-empty Bill Graham Civic.

While its fan base, at least on this side of the Canadian border, is shrinking in size, it’s still mighty large in terms of enthusiasm. The band members _ vocalist-guitarists Steven Page and Ed Robertson, bassist Jim Creeggan, multi-instrumentalist Kevin Hearn and drummer Tyler Stewart _ were greeted like heroes as they took the stage and performed an energetic rendition of “Wind It Up” (from the newly released “Barenaked Ladies are Me”).

After touching upon its third album, 1996’s “Born on a Pirate Ship,” with the bizarrely sweet reminiscence “The Old Apartment,” the group cranked up the comedic dial with a funny anecdote about spending a day in San Francisco. That rolled straight into one of Page and Robertson’s famed ad-lib songs, which had the crowd rolling with laughter.

The Ladies then reached to their major-label debut, 1992’s “Gordon,” for “The King of Bedside Manner.” That song turned out to be one of this evening’s major musical highlights, as the musicians took this rollicking country number and sewed in a jazzy part from Van Morrison’s “Moondance” and a snippet of Styx’s corny classic rocker “Mr. Roboto.”

The group moved next to 1994’s “Maybe You Should Drive” for “Life, in a Nutshell,” a warm, friendly country-pop song that wouldn’t sound out of place on a Tim McGraw record _ unless, of course, one listens closely to the lyrics.

Following a stripped-down acoustic segment, which produced a sensational version of “Be My Yoko Ono” that came complete with Ono-style screeching and wailing, BNL got into a skit that was clearly inspired by “West Side Story.” The musicians went from singing and dancing to singing and dancing and fighting, climaxing when Page broke a bottle over Robertson’s head.

As the laughs were dying down, BNL immediately started mining the hits and played crisp renditions of such notables as “Pinch Me,” “It’s All Been Done” and “One Week.”

The two encores mixed hits (”Brian Wilson,” “If I Had $1,000,000″) and humor (a laugh-out-loud funny cover of “Feliz Navidad”) in a fashion that illustrated exactly why these fans love seeing Barenaked Ladies.