What did we do for reliable surprises before the New Playwright's Theater? The brisk little spot at 1742 Church St. NW, now gives us "Bride of Sirocco," a zany, sometimes inspired successor to last summer's mini-revue. It plays Wednesdays through Sundays at 8 p.m.

Watching the neat, combined skills in Tim Grundmann's creation. One recalls the legend of the Rodgers and Hart "Garrick Galeties" bow, which with simplicity, direcness and imagination set a fresh tone for the revues of the '20s. Here, too, are unknowns truning poverty into sparkle.

The better sketches include a spoof on Verdi, "II Tarzani," will Tarzan's Jane tempted to the riches of an American singing carrer, and Cheetah heartbroken when Tarzan follows her with his Pan Am flight bag and bananas. Television oldies also inspire a "Bad Seed" comment not unconnected with TV ads.

Using other TV inanities, the Miss America Contest and "Let's Make a Deal," "Papal Pageant" shows Grundmann's deftness in using such a mix without religious offense. When Tanis Roach asks the TV audience, "Have you ever seen a happier Pope?" the humor is aimed not at the papacy but at our ghastly TV.

Apart from writer-composer-lyricist Grundmann at his piano, there are only four performers, highly individual but mutually engaging. A perky veteran of the earlier "Sirocco." Roach uses her face with marvelous versatility. A. David Johnson has a controlled geniality which could melt ice. Jan Frederick Shiffman has a bearded, puckish grace. Newcomer Dana Vance is a true comedienne of mercrucial aplomb.

NPT has been using its flat space in a former gym cleverly. For the first time the bleacher seats are set in traditional style, facing an ingenious homespun setting by Russell Metheny, including a curtain of headgear which serves several improvisational turns (real ones for a change) to amusing effect, Ken Bloom's direction. William J. Turnbull's lighting and even the program notes ("Who's Who Not in the Cast") contribute to an utterly delightful, witty novelty. The run will end Jan. 23, so get after reservations now at 232-1122.