Along with the Roots Picnic - the fourth annual all-day extravaganza is at the Festival Pier on June 4, with The Roots, Nas and Ariel Pink performing, among many, many more - there's also an eve-of-the-Roots Picnic jam session.

This year, the Roots appetizer - or as it's being called "Tapas: A Roots Pre-Picnic Treat" - will squeeze into the extremely cozy confines of South Street's The Legendary Dobbs. That's the landmark space on 3rd and South that formerly housed J.C. Dobbs, the club where Nirvana and Bo Diddley once raised a racket in its 1980s and 1990s heyday. And it's not far from the street corner where Tariq "Black Thought" Trotter and Ahmir "?uestlove" Thompson (who by the way, layed with Elvis Costello last night in New York) used to busk in the same time period, when they were fresh out of Philadelphia's High School for the Creative and Performing Arts.

The Friday June 3 gig won't be a proper Roots show per se, but one of the loose-limbed jam sessions in which the Philadelphia and Late Night With Jimmy Fallon band specialize, with announced guests including Dice Raw, J Period, Brass Haven and Chin Chin, and others whose names can not yet be revealed. Tickets are on sale at the Legendary Dobbs web site.

Previously: Birthday Bob