By Stephen Brookes • The Washington Post • September 6, 2008

Chaka KhanAARP is pulling out the stops for its gargantuan 50th anniversary celebration this week, bringing a slew of big-name (and over-50) performers to the Washington Convention Center. Things got off to a spectacular start Thursday night, when singers Chaka Khan and Natalie Cole put on powerful -- if very different -- back-to-back sets before a crowd of thousands.

The impossible-to-pigeonhole Khan opened the evening with an hour-long set that jumped from rhythm and blues to disco to funk, tearing into her 1984 hit "I Feel for You" and delivering Rufus-era blockbusters from "Do You Love What You Feel" to the iconic "Tell Me Something Good." Khan's voice is still a thing of ferocious power, and at 55 she's hardly over the hill. But in spite of a flashy, gazillion-watt light show that could easily stun a small country, she turned in a rather tepid set. As if on autopilot, she never put her spectacular pipes to full use, and only really connected with the audience with a closing, heartfelt version of "I'm Every Woman."

Cole, who on Tuesday is releasing more American standards on "Still Unforgettable," was a different story entirely. Backed by a small orchestra, Cole sang elegant, eloquent classics, including "Come Rain or Come Shine" and "All the Things You Are," as well as lesser-known gems like Carmen McRae's "Coffee Time." Sophisticated but warm and unpretentious, Cole, 58, had the huge crowd with her from first note to last, and brought the house down with a moving duet of "Unforgettable" -- sung, as on her huge hit version of it, with a tape of her father, the late Nat King Cole.