David Grisman’s “dawg” music, the name he gave his once unique and eventually influential mélange of bluegrass, jazz, folk, and western swing stylings, is about as close as things come to a sure-fire good time — the sonic equivalent of watching amazingly spry octogenarians cut a rug. It’s almost unnaturally nimble and technically advanced, and yet the abiding vibe is one of traditional, practically corny warmth, like an embroidered sampler or a pancake breakfast. 

It’s a formula you don’t want to mess with, in other words, but old friendships in twilit careers frequently override common sense and sometimes produce something worthwhile anyway. So it is with the 64-year-old Grisman and his duet partner at the Cedar Cultural Center tonight, 65-year old John Sebastian. College buddies back at NYU in 1963, they played together in the Even Dozen Jug Band, a septet founded by guitarist Stefan Grossman that also featured singer Maria Muldaur (who on to the Kweskin Jug Band and solo fame with “Midnight At The Oasis”), former Blood, Sweat and Tears member Steve Katz and ragtime music arranger Joshua Rifkin.

John Sebastian, of course, is in the Rock and Roll Hall of Fame for the incandescently winsome singles he churned up with the Lovin’ Spoonful. Daydream” and “Summer in the City” only scratch the surface of this durable batch, which also include such stoned-smile artifacts as “Did You Ever Have to Make Up Your Mind?” “Rain on the Roof,” “Do You Believe in Magic,” and “Nashville Cats.”  Sebastian’s dazed and confused solo performance at Woodstock — an area of the country where he has resided for decades now — and his novelty hit with the title track for “Welcome Back Kotter” extended his career, but it was the Spoonful stuff that planted his legacy.

Two years ago, the two got together for “Satisfied,” an aptly-named recording that harkens back to their jug-band roots and nods to the advances each has made since then. Among the record’s 14 songs are old Spoonful numbers like “Coconut Grove,” Grisman songs like “EMD” and “Dawg’s Waltz,” Mississippi John Hurt’s title track, and public domain material such as “John Henry.” For the most part, Grisman is on mandolin and Sebastian plays guitar and harmonica.

It’s shaggy dawg music, and while I’d frankly prefer Grisman’s fine quintet or a vintage version of the Lovin’ Spoonful, the former will come through town at some point in the near future and the latter will never be recaptured. This particular engagement doesn’t guarantee a good time for all, but I’ll bet Grisman and Sebastian have fun, and, given their talent and respective track records, it might be contagious.

Here are the pair performing excerpts from the Spoonful hits “Coconut Grove” and “Daydream” back in October.

Here they are on the bluegrass standard “Shady Grove.”

David Grisman and John Sebastian at the Cedar Cultural Center, p.m. Tickets are $40 general admission and $55 for “front and center.”