Very few bands have as dedicated and cult-like an audience as the Grateful Dead and a multitude of adjacent bands encircle Planet Dead like happily humming satellites. Like many great cults, the death of the beloved leader has done nothing to stop the ride and these extra-orbital ancillaries have a built-in audience in quadrants of the known live music universe. And what a fine trip that must be and who am I to piss on the passions of such dedicated pilots? Besides, in the right company, I will admit to enjoying some of the Dead's oeuvre and no record do I enjoy more than Workingman's Dead, the band's 1970 paean to folklore Americana and the emergent Bakersfield speed-country sound of Buck Owens and company. So I can happily endorse this show tonight at 9 p.m. at Humbrews, where the Grateful Bluegrass Boys intend on performing that LP in its entirety. Featuring members of Poor Man's Whiskey and Hot Buttered Rum, these players have the chops to make the strings sing ($10).