What is the Society of Seven — now marking its 40th anniversary in Waikiki — best known for?

Here's a pop quiz:

A. Broadway medleys, complete with costumed glory.

B. Impressions of show biz legends, past and current.

C. A change in membership, every few years.

D. Longest same-room run in Waikiki.

E. All of the above.

If you answered E, you're spot-on right.

Indeed, the SOS's Fabulous 40 celebration — under way this month — is all about change, vision, reinvention, challenges in the savvy shows under the stewardship of group co-founder Tony Ruivivar.

Musical montages remain a staple; the SOS still makes a good impression; and members come and go often as the tides shift. Still happening, after four decades, at the Outrigger Waikiki's Main Showroom.

Ruivivar and co-founder Bert Sagum, the only two originals remaining in the "classic" group, will bring 20-year members Wayne Wakai and Hoku Low, along with newcomers Vince Mendoza and Mike Laygo, to the Outrigger stage for a guest appearance next Wednesday and Thursday. Confusingly, this original group now is based in Las Vegas, prepping to launch a new show at the Stratosphere's Theatre for the Stars, in a 3 p.m. slot, this month.

Meanwhile, the spinoff group — SOS Las Vegas, which was to be ensconced in the gambling capital, but is in residency at the Outrigger — will share the stage with their mentors, marking the first time both acts will co-star. The bulk of the show will be shouldered by SOS LV, led by Richard Natto; but the gig introduced to Honolulans new lead singer Laygo, who replaced Mike Escueta, who was Gary Bautista's successor. Bautista died Jan. 30, 2006.

Also new: Mendoza, ex-member of the Aura 'ohana, who spells Randy Abellar. The fresh keyboarder is Roy Venturina, a musician from Los Angeles, who is in the midst of relocating to Vegas (so won't be here); he replaces Roy Guerzo, who bowed out of the group last year.

For residents, the two-night special is a bargain to see the SOS this month - a special kama'aina package includes the show with a burger and soft drink at Jimmy Buffett's at the Beachcomber, across the street at the Ohana Waikiki Beachcomber Hotel.

I've covered the SOS since its origins, reviewed and interviewed them and lived through their accidents, some deaths, a few emotional departures and some happy arrivals.

I've seen them in Los Angeles and in Las Vegas and count these memories — and benchmarks — so have witnessed its legendary craftsmanship: