When several Montgomery County students organized a performing group called Rainbow to offer "musical revues for all occasions," they never imagined the variety of occasions for which they would be asked to perform.

"This is our second year and you name it. We've performed in overheated nursing homes, frigid schools and church rooms, had to work with a piano that was literally on its last leg--only to financially break even," says Gerald Payne, Rainbow's producer-manager. "Our limited resources keep us from expanding our productions, but we are still averaging one concert a week throughout a year's time."

Rainbow's revues have included instrumental, vocal and dance solos as well as duets and ensembles of popular tunes to piano accompaniment. They are performed mostly by students from Good Counsel High School in Wheaton and Holy Cross High School in Kensington.

In the beginning, the group performed a lot of Judy Garland songs to nursing home audiences. Now, more than a year later, its audiences include preschoolers at schools and churches, social and business clubs, and handicapped and senior citizens. Rainbow sometimes performs at no charge and at other times receives a fee for its work.

The group gives its members a chance to perform in public, to sharpen their vocal and dance skills and to bring joy to others. "At the very least," says Payne, "we want to teach them what it's like to give."

As many as a dozen performers in colorful, loose-fitting tops, pants and shirts sing and dance such songs as "Boogie Woogie Bugle Boy From Company B," "Smile," "Singin' In the Rain" and "My Mama Done Told Me."

Paul O'Brien, 17, of Silver Spring, enlivens several of the group's songs with his trumpet. John Mancuso, musical director for the Bethesda Community Center's production of "The Fantasticks," which opens tomorrow, recently joined Rainbow as its pianist.

Rainbow, in many respects, is a family affair. The entire O'Brien family has performed: parents Paul and Annamae, daughter Karen, 14, and sons Paul and Kevin, 15.

Teresa Payne, 17, is one of the three daughters of Gerald Payne's performing family. Teresa has performed at the Harlequin Dinner Theatre and at the Kennedy Center with the Washington Opera. A singer and dancer, Teresa says she is eyeing a career on Broadway. Her two sisters, Linda, 19, who is studying voice in college, and Mary, 16, also perform with Rainbow. Gerald, a veteran of more than 15 local community theater productions, emcees each performance with humor, explanations or introductions--whatever the occasion calls for--and sometimes sings.

A brother-and-sister team, MaryLee and Joey Luna, also performs in Rainbow. "I've gotten to be around more people now and I think I have really surprised my mother. She never thought I would do this kind of thing," Joey Luna says. MaryLee plays guitar.

Manager Payne counts only five trained musicians, two trained dancers and no trained actors among Rainbow's performers. But some alumni of the group have attained professional status. Former member Pat O'Donnell is a concert pianist and Linda Payne won a National Association of Teachers of Singing vocal competition. She attends Shenandoah College.

At one time an all-female group, Rainbow now is open to all performers of high school or college age, says Payne.

Rainbow has received small grants, but Payne says the group survives on donations and "out-of-pocket money." The Montgomery County Arts Council gave the group a grant, which was used to buy costumes.

The group is donating a performance for the Montgomery County Arts Council auction Saturday and will perform at Inwood House, a halfway house, Feb. 28. photos 1&2: Rainbow member Kevin O'Brien, a student at Good Counsel High School in Wheaton, in "Nothin' Like a Dame" at the Silver Spring Senior Center; and seniors Jeannette and Max Seidlitz enjoy the musical group's show.