June, 1979. As noted jazz fan Hugh Hefner addressed the crowd at the Playboy Jazz Festival in Hollywood Bowl -- the first since a legendary gathering of jazz royalty at Chicago Stadium in 1959 -- he had a sudden brainstorm. Reportedly catching his staff off-guard, Hefner proclaimed that the festival, supposedly a one-shot deal, was going to become an annual event

And so it has, re-appearing every June since, a big, two-day musical block party for more than 17,000 music fans and sun-worshippers.

With Darlene Chan, in tandem with Playboy and the Los Angeles Philharmonic Assn., producing the festival since its inception, the Playboy fest has maintained a remarkable, ritual-like consistency over the decades. The music is continuous from mid-afternoon until late at night, and common streaks of energy often run through several seemingly unrelated acts.

Some have alleged that the Playboy has evolved into less of a jazz festival and more of a general music showcase. But an examination of program books over the past 30 years reveals that the event has mostly stuck close to its original mission of presenting a wide selection of acts from the jazz spectrum, which itself has expanded over that period. Yes, there have been a few more excursions beyond the genre in recent years than before, but not enough to topple jazz as the predominant idiom.

This is also true for the 2012 lineup on June 16-17, which remains weighted toward various definitions of jazz with lots of inroads from elsewhere -- Keb' Mo's rootsy soul, Robin Thicke's sensual pop/soul, KG Omulo's Afro-funk-reggae, always-unclassifiable Ozomatli, among others. Most encouragingly, the 2012 edition revives the idea of loading the lineup with such all-star combinations as Quincy Jones' polyglot Global Gumbo All-Stars, the hard-core jazz-rock of Spectrum Road, veteran post-boppers the Cookers, and of course, perennial emcee Bill Cosby's Cos of Good Music.

As the years go by, the festivals become a blur of of memories, with some indelible performances rising to the surface: the electrifying, one-time-only 1985 Sing Sing Sing vocal quartet of Jon Hendricks, Dianne Reeves, Bobby McFerrin and Janis Siegel; George Benson rocking the Bowl with Herbie Hancock and Branford Marsalis in 1986; Reeves again, achieving ignition with cousin George Duke in 1999; Al Jarreau taking off for the first time with Dave Brubeck on "Take Five" in 2003; or Eddie Palmieri's outrageously swinging "Listen Here" in 2006.

Hopefully 2012 will have more moments of total ignition like these.