Off-Broadway's Playwrights Horizons has taken the plunge -- and it's paid off. Christopher Kyle's comedy, Plunge, which opened the season Sept. 28, has just been extended past its Oct. 12 announced close to Oct. 19.

Kyle has been on the scene for a while (Boca, 1989's Dessert At Waffle House, Breakfast Anytime) but came to strong New York attention in 1995 with his multi-media The Monogamist, also at Playwrights Horizons. Plunge, which began previews Sept. 5, looks at a weekend in the country for four college friends and an unexpected houseguest. Ron Lagomarsino directs. Cast in the show are Jessica Hecht, Bruce Norris (Sin at Off-Broadway's Second Stage Theatre), Taylor Nichols, Robert Bagnell and Ashley Crowe (Prelude To A Kiss). Hecht recently left Last Night Of Ballyhoo and is also known for her recurring role as Susan on TV's "Friends."

Desiging Plunge are Don Holder (lighting), Rob Odorisio (set) and Jennifer von Mayrhauser (costumes).

Also on tap for the Playwrights Horizons season:
Lynn Nottage's Crumbs From The Table Of Joy played at the Second Stage Theatre Off-Broadway in 1995. Also that year, the Vineyard Theatre staged her Por'knockers. Mud, River, Stone (Nov. 21 Dec. 28, opens Dec. 14), to be directed by Roger Rees, follows an African American couple honeymooning in South East Africa -- only to encounter "an unexpected and bizarre adventure" after taking a wrong turn on a muddy road. Director Rees appeared on Broadway in a recent revival of The Rehearsal.

Gloria Muzio, who staged Other People's Money, will direct Richard Dresser's Gun Shy, Jan. 13-Feb. 22, 1998 (opens Feb. 1, 1998). The "edgy comedy" concerns a divorced couple whose separation proves as unsuccessful as their marriage. Other plays by Dresser include The Downside, Alone At The Beach and Bed And Breakfast. His Below The Belt starred Judd Hirsch Off-Broadway and was produced by San Diego's Old Globe Theatre in May.

Tom Donaghy's Northeast Local played at Lincoln Center Theatre in late 1995; his Minutes From The Blue Route was a minor hit for the Atlantic Theatre Company earlier this season. Other plays include Down The Shore and The Dadshuttle.

From Above (April 17-May 24, 1998, opens May 10, 1998) has a "Martin Guerre"-style twist to it: a young widow is approached by an appealing stranger who claims to be her husband.

One surprising aspect of the 1997-98 Playwrights Horizons season is the absence of a musical, since recent years have brought viewers the award winning Violet, Floyd Collins and Jack's Holiday. Perhaps a musical will spring out of the "New Theatre Wing" series, held on the second floor Studio Theatre. Now in its 11th season, the Wing "provides playwrights, composers and lyricists the opportunity to develop their newest, and often boldest, work."

Tim Sanford serves as artistic director of the 26-year-old Playwrights Horizons, located at 416 West 42nd St. For more information about Playwrights Horizons' upcoming season call (212) 279-4200.

-- By David Lefkowitz