THE KENNEDY CENTER kicks off more than two weeks of professional and amateur productions Friday in its 10th annual National Children's Arts Festival, called Imagination Celebration 1986.

Professional productions include the world premiere of "A Good Life," a musical theater piece commissioned by the Kennedy Center; "Song for the Navigator," a story recounting the adventures of a Micronesian youth, performed by the Honolulu Theater for Youth; a marionette production of Rudyard Kipling's "The Jungle Book"; and the live broadcast of four plays written by winners of Children's Radio Theater's eighth annual Henny Penny Playwriting Contest, hosted by actress Tina Yothers of NBC's "Family Ties."

At a gala Wednesday in the Terrace Theater, Jim Henson, creator of the Muppets, will be presented with the Kennedy Center Award for excellence in programming for young people. He'll be accompanied by a black-tied Kermit the Frog.

The gala will also include scenes from "A Good Life," with book and lyrics by Henson's longtime "Sesame Street" collaborator Jeffrey Moss, and music by Stanley Silverman; and from "The Jungle Book," a production by the Center for Puppetry Arts of Atlanta.

Other special events include two big ones for free in the Grand Foyer -- a Family Fun Day on April 26, offering three hours of varied entertainment; and a Very Special Arts Festival of performances and workshops on April 29 for both disabled and nondisabled persons.

Other items of interest:

The Young Performers Showcase on April 27 in the Theater Lab features winners of Woodward & Lothrop's Star Student Talent Contest: ballet and jazz dancer Heidi Emmer; spiritual singer and pianist Tyrone Ford; modern dancer Valerie Miller; drummer Eric Northern; and pianists Diana Soriano and Sara Takagi.

The showcase also introduces the Kennedy Center's new PCY Acting Ensemble of 16 local teen-agers chosen by audition. The troupe makes its debut with "The Absolute Dream," a play they created with resident playwright Jeff Church. In the play, a high school student council president asks, "How would you like to change your life?" The varied answers are the basis of the script. Performances will be sign-interpreted. CAN YOU IMAGINE?

Here's a rundown of public performances during the Imagination Celebration, which runs through April 29.

Events in the Grand Foyer are free. Free tickets are required for performances of the Children's Radio Theater, "A Good Life" and the Young Performers Showcase, all in the Theater Lab. Tickets are $7.50 for "The Jungle Book" and "Song for the Navigator," and $20 for the Imagination Celebration Gala, all in the Terrace Theater.

FRIDAY -- Children's Radio Theater production of four scripts that won the eighth annual Henny Penny Playwriting Contest, 7:30 in the Theater Lab.

SATURDAY -- Wyngate Elementary School Chorus of Bethesda, 11:30 a.m. in the Grand Foyer.

SUNDAY -- "The Jungle Book," 3 p.m. in the Terrace Theater.

WEDNESDAY -- Imagination Celebration Gala, including scenes from "The Jungle Book" and "A Good Life" and a special award to Jim Henson, 7:30 in the Terrace Theater.

THURSDAY -- "The Primary Movers" (a dance company) of Chevy Chase, noon in the Grand Foyer, and "The Jungle Book," 7:30 in the Terrace Theater.

APRIL 18 -- "Children of Peace," choristers of Auburn, Ind., noon in the Grand Foyer, and the world premiere of "A Good Life," 7:30 in the Theater Lab.

APRIL 19 -- Iroquois High School Band of Elma, N.Y., 11 a.m. in the Grand Foyer; "The Jungle Book," 11 a.m. and 1 p.m. in the Terrace Theater; "A Good Life," noon and 2 p.m. in the Theater Lab.

APRIL 20 -- "Song for the Navigator," 3 p.m. in the Terrace Theater.

APRIL 21 -- "Song for the Navigator," 7:30 p.m. in the Terrace Theater.

APRIL 22 -- "A Good Life," 7:30 p.m. in the Theater Lab.

APRIL 23 -- "Song for the Navigator," 7:30 in the Terrace Theater.

APRIL 25 -- Dyersburg (Tenn.) High School Band, 6 p.m. in the Grand Foyer; "A Good Life," 7:30 p.m. in the Theater Lab.

APRIL 26 -- Family Fun Day (music, mime and other entertainment), 10:30 a.m. to 1:30 p.m. in the Grand Foyer; "A Good Life," noon and 2 p.m. in the Theater Lab.

APRIL 27 -- Young Performers Showcase featuring Star Student Talent Contest winners and Kennedy Center's PCY Ensemble performing "The Absolute Dream," an original play, at 3 and 7:30 p.m. in the Theater Lab.

APRIL 29 -- Very Special Arts Festival (performances and workshops for disabled and nondisabled performers), 10:30 a.m. to 2:30 p.m. in the Atrium and Grand Foyer.

For more information, call 254-3600 or 254-7168.