"Thanks for the memories; of happiness and heart; of humor sweet and tart; of jokes that bite and shed some light, even when they smart; we thank you so much."

Those are the words first lady Nancy Reagan sings to the tune of Bob Hope's signature song in a three-hour NBC special celebrating Hope's half century of broadcasting for NBC, and also his 85th birthday.Happy Birthday, Bob -- 50 stars Salute Your 50 Years with NBC, airs on Ch. 2 tonight at 7 p.m.

On the theory that nothing succeeds like excess, there actually are about 75 stars performing, 33 of them live and the rest on tape.

Among the stars are Elizabeth Taylor, Lucille Ball, Barbra Streisand, Burt Reynolds, Ann-Margaret, Ginger Rogers, Shirley MacLaine, Betty White, Bea Arthur, Shelley Long, Tony Randall, Sammy Davis Jr., Michael Landon, Dinah Shore and Jonathan Winters.

Dorothy Lamour, the sarong girl that Hope and Bing Crosby chased in their "Road" pictures, will be on hand, as will Hope's more recent sidekick, Brooke Shields.

The first lady appeared live to serenade Hope. Former presidents Jimmy Carter, Richard Nixon and Gerald Ford also turn up.

President Reagan appears on a video, "from one old timer to another," and saying:

"I've been wracking my brains,