When was the last time you saw Wu Tang Clan — the entire collective — perform live? Or for that matter, listen to Nas’ inimitable flow as he spit bars in the flesh? Or consider the unthinkable: watching ‘Ms’ Lauryn Hill, now more famous for various and sundry off-stage peccadilloes than her music, put on a coherent show?

If either of these questions momentarily leave you stumped, then you may want to consider dropping a few coins (well, at least $100, to be exact) on Rock the Bells, the traveling paean to hip-hop’s golden era that has rocked stages countrywide for the last seven years. Between now and next Saturday, the music festival wraps up its summer run at Governor’s Island in New York Harbor and Boston.

Live music celebrations have always been de rigueur in the music industry. But ever since 1969, when Woodstock immortalized the concept of a multi-day music fest and enshrined the idea of uniting disparate acts in a single venue, the format has been progressively adapted to suit the times. The end result is a festival like Rock the Bells, which follows other annual music events that have also attempted to replicate the Woodstock vibe, albeit to varying degrees of success.

Rock the Bells has certainly outlasted its troubled female counterpart, Lilith Fair. The all-girl revue rose to prominence in the late 1990s, only to be mothballed, revived, and then retired anew.

And unlike Coachella — which culls acts from the cream of the music industry and has in the past featured a decidedly eclectic mix of names such as Madonna, Jay-Z, and Paul McCartney — Rock the Bells is a departure from other events that populate the music scene. Its aesthetic is an unusual amalgam (a collision, really) of the old and the new; the known and the unknown; the hip and the square. And it’s all hip-hop.

Perhaps the most intriguing aspect of the festival is the avowed dedication to promoting names that, while easily recognizable, aren’t exactly topping the charts anymore. The homage Rock the Bells pays to classic hip-hop (read artists that rose to fame prior to 1997) confers upon its acts something of an eminence grise status. Truthfully, many of the headliners almost fall into the “golden oldies” category of rap.

Not that being long in the tooth is a bad thing: things have certainly worked out well for the ageless talent embodied by Chicago and Earth, Wind & Fire. Proving that you’re only as old as you feel, the AARP-certified Rolling Stones certainly show no signs of slowing down anytime soon. But the entertainment industrial complex is for its fickleness and veneration of youth, and its proponents rival Peter Pan for their refusal to grow up. For that reason, age carries something of a stigma.“I think that’s the gamble that headliners have to take if they want to headline [Rock the Bells], Oliver Wang, a sociology professor at California State University-Long Beach, told theGrio.

“The festival isn’t very shy about revealing its biases in terms of which era of hip-hop it thinks was king,” said Wang, a hip-hop aficionado who authored Classic Material: The Hip-Hop Album Guide. “The fact that this year’s line-up of 12 ‘classic’ albums has only one album recorded in the last 10 years tells you everything.”

And because the preferences of the organizers are clear, artists take a calculated risk by choosing to appear under the Rock the Bells banner. So while Common (last seen at a White House’s poetry reading) and Erykah Badu (recently spotted stripping down in the nude at the scene of an American president’s assassination) may not be as big as they once were, they get an appreciative audience and a prominent event from which to perform their semi-classic hits.

A frequent Rock the Bells headliner is Talib Kweli, one of conscious hip-hop’s most prolific acts and one that straddles the realms of indie and mainstream rap. Along with the multi-talented Mos Def, he forms BlackStar, which hasn’t recorded a new album in several years but is a perennial crowd-pleaser.

A big draw to the music festival is Wu Tang Clan, the closest answer hip-hop has to Voltron: powerful as individual fighters but nearly unstoppable when fully formed. Wu Tang is now less of a music group than one of music’s most recognizable brands – and one that refuses to die. Rock the Bells’s first concert in 2004 reunited the Monks of Shaolin, and while they are not scheduled to perform as a group at the last two performances,the presence of GZA, Raekwon and Ghostface give Wu Tangers at least modest hopes for an impromptu reunion.

Oh, and then there’s Lauryn — sorry, “Ms. Hill.” Never mind the fact that she hasn’t done much of note music-wise since her Grammy-sweeping breakthrough. If nothing else, the former Fugee has become infamous for erratic stage performances, if not actual studio recordings. Her fans have noticed, and they are not pleased.

And because tomorrow’s big stars have to start somewhere, the event can also lend cachet to the underground acts — such as Murs and the controversial yet searing afro-Peruvian lyricist Immortal Technique — that permeate lounges and the iPods of hipsters everywhere. This “dirty backpack” vanguard gets a prominent stage that has the ability to give impetus to their careers.

After earthquakes and hurricanes (all in the same week!), some good music could be just the antidote for frayed nerves in need of soothing. If nothing else, Rock the Bells might be a welcome distraction from an otherwise dark reality.