March 21, 1982

The Organization of Petroleum Exporting Countries, moving to reduce the worldwide surplus of oil and bolster prices, agreed today to cut production by about 700,000 barrels a day. It was the first formal production agreement by the 13 OPEC members. The reduction was greater than had been expected, and included a cut of 500,000 barrels a day in Saudi Arabia's production ceiling, to seven million barrels a day. The action would reduce OPEC's total daily output to a maximum of 17.5 million barrels a day, from its estimated current production of 18.2 million barrels. Only three years ago OPEC was producing 31 million barrels of oil a day.

The Reagan Administration said today that it had information that three months ago Fidel Castro, the Cuban leader, ordered a step-up in arms shipments to insurgents in El Salvador in an effort to disrupt the March 28 elections there. The State Department also said it had learned that after a meeting in Havana in mid-December between the Cubans and Salvadoran guerrilla leaders, ''extreme leftist groups throughout Central America were mobilized to support the effort.'' A department spokesman declined to make public the source of its information, saying it was based on sensitive intelligence data the release of which would compromise sources and possibly endanger the lives of intelligence operatives. However, along with the report the department released a compendium of comments in support of the charges of Nicaraguan involvement from ''distinguished Americans'' who it said had seen the secret evidence.

It is midnight on a Saturday night, and the cabaret at Palsson's Upstairs is crowded. The lights dim and the spotlight shimmers against the backdrop, a glittering curtain of tinsel. To the tune of ''It's Almost Like Being in Love,'' Gerard Alessandrini and Nora Mae Lyng deliver their verdict on Broadway's reliance on the tired old tried-and-true: ''The backers who finance a show All agree people like what they know So instead of what's new They just redo the few That were famous in 1940 - Not more than 1950 - Almost like 1948.'' The song is one of many in ''Forbidden Broadway,'' a satirical Off-Off Broadway revue that skewers Broadway hits and their stars. Whatever the merits of its charge that Broadway suffers from a derth of fresh ideas, the same could hardly be said of Off Broadway and Off Off Broadway theater. ''Forbidden Broadway'' is packing them in on West 72d Street, while a bumper crop of plays and musicals is flourishing at smaller theaters all over town. Meanwhile, however, Broadway is limping through a troubling season. An ominous number of Broadway closings has coincided with an unusually long dry spell between major openings, and the contrast with the creative ferment elsewhere seems particularly marked. ''Off Broadway really is where most of the excitement is,'' says Bob Gunton, the star of ''How I Got That Story,'' which is currently ensconced at the Westside Arts Theater.

EQUITY theater in the county may temporarily be a thing of the past because of the cancellation of the last three plays of the 1981-82 season of the Main Street Theater company in White Plains, Westchester's last Actors' Equity troupe. But that professional acting group's artistic director said he not only was encouraged about the future of theater as a whole in the county but also was extremely hopeful that the closing of his group would be temporary. His comments shed light on the dilemma created, on one hand, by the closing of a number of theaters in the county in the last few years and, on the other, by the presence in the area of many sophisticated, highly educated, well-to-do would-be theatergoers with no place to go nearby. Stephen Rosenfield, the artistic director of the Main Street Theater, in an interview last week in his brownstone apartment on Manhattan's East Side, said that his board of directors, although making the decision to cancel the season, had still reserved the option to continue the theater company's performances when new money could be obtained. (The plays omitted were Noel Coward's ''Private Lives,'' Chekhov's ''Uncle Vanya'' and a comedy that had not been selected.

IN every direction, as far as the eye can see, the unmistakable imprint of Japan's largest auto maker is evident in this city that fittingly bears the company name. More than 35,000 of the Toyota Motor Company's 48,000 employees worldwide work here, 150 miles west of Tokyo. Rows and rows of lookalike houses that Toyota provides for its married workers at cutrate prices form a kind of corporate Levittown. Company dormitories can house 20,000 bachelors and another 1,500 units are available for unmarried women workers. Then, too, there is the company stadium that seats 30,000, the company baseball fields, the company gymnasiums, the company swimming pools, company tennis courts, even company sumo rings.