THIS IS THE FIRST thing I've ever won in my life," says Janet Davidson, who was one of 19 actors who won the chance to perform Monday in the 5,001st performance of "A Chorus Line" at the Shubert Theater on Broadway. "It was better than the lottery!"

In July, the producers of "A Chorus Line" sent letters to nearly 400 theaters in the country that have produced the musical; 800 performers returned photos and resumes to be eligible for the contest. The winners were picked at random from a sequined top hat, and Davidson, who played Bebe in last year's Toby's Dinner Theater production of "A Chorus Line," was flown to New York, fitted for costumes and taught the dance combinations for "What I Did For Love" and the spectacular finale number, "One". Davidson and the other winners performed the two numbers with the Broadway cast before an audience that included producer Joe Papp, Celeste Holm, Barbara Cook and "La Cage aux Folles" stars Peter Marshall and Keene Curtis.

An elated Davidson returned to her suburban Maryland home Wednesday with lots of "A Chorus Line" souvenirs -- and the shoes she danced in on Broadway. "I'm pretty content living here," says Davidson, who sells real estate during the day and performs dinner theater at night (she plays Agnes in Toby's current production of "George M!"). But the actress admits that one night "gave me the itch to want to audition for Broadway."

Haskell Harelik, the subject of his grandson Mark Harelik's endearing play "The Immigrant: A Hamilton County Album," died Sunday. He would have been 100 next month. Mark Harelik flew back home to Hamilton, Texas for the services; his understudy, Washington actor Steve Dawn, went on at Arena's Kreeger Theater Tuesday night, and by all accounts did a fine job. Harelik was due back for Wednesday's matinee and was expected to do some rewriting to acknowledge his grandfather's passing. The last performance of "The Immigrant" is 7:30 Sunday.

"I stand on this streetcorner like Major Barbara with her bell and bucket," said Studio Theater founder Joy Zinoman at last Friday's dedication of Studio's new theater. Zinoman's dramatic delivery could be heard even above the midmorning din at the corner of 14th and P NW. As volunteers passed out plastic glasses of champagne for a toast (attracting the attention of a few passersby), Zinoman called the new theater her "bud of love" which "by summer's ripening breath -- that means October -- may turn into a blossoming flower when next we meet."

Zinoman also introduced theater designer Russell Metheny, architects Devrouax & Purnell; and contractors Bruce Auger and Joe Irish, who are swiftly transforming the Petrovitch Auto Repair plant into an attractive theater. "This is a theater district -- it really is," Zinoman said. "Won't somebody please open a restaurant on this block -- please?" While the dedication and tours were decidedly upbeat, Zinoman expressed concerns about a few things that need to be resolved before the scheduled October 14 opening: Studio still needs boosted service from Pepco, a certificate of occupancy, and completion costs have risen to $750,000 from the projected $500,000. An additional $268,246 is needed; contributions can be made by calling 265-7412.

Meanwhile, in Virginia, a young theater is stirring in its nest. American Showcase Theater has just joined the League of Washington Theaters and is building its own theater at Station Shops in Alexandria, a block away from the Duke Street Metro. "For the first time we are in an easy-to-find location," says artistic director Jill Kamp, who says she now needs to raise $50,000 to finish the space. American Showcase Theater will operate under an Actors' Equity Small Professional Theater contract. The plays: Athol Fugard's "Blood Knot" (begins October 16); a multiracial production of "The Fantasticks" (December 4); and Harold Pinter's "Old Times" (February 26).

Source Theater wound up its successful seventh annual Washington Theater Festival Tuesday night with an awards ceremony at the Omni Georgetown Hotel. Director Raoul Rizik's production of Mario Vargas Llosa's "The Spinster From Tacna" won Best Production, Best Actress (Ramona Rhoades) and Best Director for Rizik, who spent five years on the translation and has long tried to interest area theaters in the play. Best new play was Paulette Laufer's one-act comedy "State of Texas," which also netted Nancy Robinette a shared Best Actress award. Best Actor went to Scott Davis in "Remedial English"; Austin Porter and Cam Magee won Best Supporting Actor and Actress, respectively, for their turns in "Oscar and Tanya." All received an awards certificate designed by Washington artist Lou Stovall. Robert Piggett won the 10-minute play competition with "Long Day's Journey Into Ice"; his prize was a digital watch -- to make sure his next play sticks to the time limit.

Bulletin Board: Ford's Theater opens its 20th anniversary season September 15 with Barbara Rush in "A Woman of Independent Means," a one-woman show based on Elizabeth Forsythe Halley's novel. The rest of the season is still being settled, but reportedly includes David Bell's musical adapation of "A Christmas Carol" . . . And good luck to Larisa Wanserski, who is leaving her position as public relations director at Ford's and striking out on her own . . . Kennedy Center is getting the Berkshire Theater Festival revival of Robert Anderson's 1968 Broadway hit "I Never Sang For My Father" stars Daniel J. Travanti, Mary Kay Place, Dorothy McGuire and Harold Gould, at the Eisenhower Theater September 1-19 . . . Channel 9 arts critic Davey Marlin-Jones is guest director of "The Dining Room" at the Totem Pole Playhouse in Fayetteville, Pa., through August 23. Marlin-Jones, who is directing a cast including his wife, Arena Stage actress Maggie Winn-Jones, has plenty of theater chops -- among other things, he was director of the Washington Theater Club for seven years . . . Arena Stage has announced the first three plays in its Stage Four series, which is devoted to the development of new works. The plays will augment Arena's previously announced season: Harvey Pekar's "American Splendor," directed by Jim Nicola (begins October 30 in the Old Vat Room); Washington playwright Heather McDonald's "The Rivers and Ravines," directed by Doug Wager (February 26, Kreeger); Ron Milner's "Checkmates," directed by Woodie King Jr. (March 18, Arena). Single tickets will be $10; a subscription costs $24.75. Call 488-3300 . . .

On Tuesday, activist/playwright Daniel Berrigan is expected at a benefit performance of "Trial of the Catonsville Nine," which is one of two plays in Potomac Theater Project's inaugural repertory season. The 8 p.m. performance at Castle Arts Center will be followed by excerpts from a new agitprop show called "Voices From the Streets" and a dinner in the theater. Tax-deductible tickets are $50; call 277-6121 . . . Tony Award-winning playwright Joseph A. Walker ("The River Niger") has chosen D.C.'s Takoma Theater to premiere his new musical "Halfway Down From Cloud Nine." The musical, featuring 30 performers from Expansions Arts Collective, is about residents of a rehab center for drug abusers; performances are Friday and Saturday, 8 p.m., Fourth and Butternut St. NW. Call 727-7146 . . .

Teamwork: Ernie Joselovitz's Playwrights' Unit is presenting two nights of staged readings at Touchstone Theater, with actors and directors supplied by Smallbeer Theater. On Monday, Donna Jerdine's new play "Rhyme and Reason" will be read; Tuesday features two one-acts, Steve Pennington's "Small Child Stood By The Rail" and Joselovitz's "The Day I Met William Inge." A donation of $2 is requested, and both evenings are followed by discussions with playwrights, actors and directors . . . "As Is," which closes Sunday after 14 weeks, is Studio Theater's longest-running play . . .