What was going on when I was born?

The Federal Reserve Board, in what it described as a move to counter the continued sluggishness in the economy, cut its key lending rate today to 9 percent, from 9 1/2 percent. The half-point reduction in the discount rate, which is the rate the Federal Reserve charges on loans to banks and savings institutions, was long expected. It was another signal that the nation's central bank wants interest rates to move slightly lower to stimulate the spending needed to begin an economic recovery. The Commerce Department reported that the economy did not grow at all in the third quarter and was unlikely to grow in the fourth quarter either. Last month it had estimated third-quarter growth of eight-tenths of 1 percent in the gross national product, the broadest measure of economic activity. (Page 29.)

The Chinese Government announced the appointments today of a new Minister of Foreign Affairs and a new Minister of National Defense. Huang Hua, who had been Foreign Minister for nearly six years, was succeeded by Wu Xueqian, who left the party bureaucracy to become first Deputy Foreign Minister last April. Mr. Huang's sudden retirement could be embarrassing for the Kremlin, because he headed a Chinese delegation to the funeral of President Leonid I. Brezhnev in Moscow. While there, he met for an hour and a half with Foreign Minister Andrei A. Gromyko to discuss the two countries' relations, the highest-level Chinese-Soviet talks since 1969.

A treasure-trove of musical manuscripts and orchestrations by George Gershwin, Cole Porter and Richard Rodgers has been discovered in a Warner Brothers warehouse in Secaucus, N.J. The find - consisting of up to 70 crates - includes scores for many important works, as well as rare and unpublished songs. In addition, the crates contain drafts of original choruses, incidental music and much thematic material. There are complete performing scores of Gershwin's ''Pardon My English'' and Porter's ''Gay Divorce,'' Fred Astaire's last Broadway musical, later filmed as ''The Gay Divorcee.'' There is speculation that there may be a complete early Gershwin work, entitled ''Half Past Eight,'' dating from 1918.

Representative Claude D. Pepper of Florida, the oldest member of Congress, has declared his intention to become chairman of the House Rules Committee, an influential post that would give him the power to shape Social Security legislation to be considered in the next Congress. Mr. Pepper, who turned 82 in September, wants the job so that he can thwart efforts to trim Social Security benefits, according to his aides. ''He realized,'' a spokesman for the Florida Democrat said, ''that the way to influence Social Security was as chairman of the Rules Committee.'' The Rules Committee decides what bills go to the House floor, and under what conditions. As a result, a shrewd chairman can wield enormous influence by forcing changes in certain bills, or simply burying them in his committee.

President Reagan, setting the stage for a budget fight with Congress, has tentatively decided to seek $25 billion to $30 billion in domestic spending cuts in next year's budget, White House officials disclosed today. The proposed cuts, which are certain to draw strong opposition in Congress, would limit the growth of spending, but overall outlays could actually increase because of inflation and other factors, such as the recession. The decision means the President will continue to focus his economizing drive on social spending. This is a key part of his evolving strategy for dealing with a new Congress that is expected to be far more resistant than the current Congress to his budgetary plans, particularly on additional cuts in domestic programs.

Despite a cut in serious subway crime over the last five months, the number of such offenses reported in New York City's system appears to be climbing toward a record in 1982. The reduction followed a special effort to fight crime, including the addition of 400 police officers to nighttime patrol, the training of 1,600 auxiliary officers for subway duty, the use of German shepherd attack dogs, the installation of closed-circuit television units and the conducting of dragnets that have rounded up thousands of offenders. Other security measures are planned as part of the system's five-year capital improvement program. But some city officials say hopes for a safer subway system are threatened by pressures on the 3,343-member transit police force from the city's fiscal troubles. Mayor Koch last week canceled plans to hire 200 additional transit officers.

Local leaders of the United Steelworkers of America, opposing their top leaders, today overwhelmingly rejected a tentative agreement that called for major concessions in wages and benefits. In return, the union would have gained more aid for laidoff workers and a profit-sharing plan. The vote to reject the contract, 231 to 141, increased the possibility of a strike when the union's three-year contract expires next Aug. 1, many local leaders and some top union officials said later. ''I'm disappointed, obviously,'' Lloyd McBride, the president of the union, said at a news conference. He said it would be ''futile'' to meet with negotiators representing the top eight steel companies until May, when regular bargaining is scheduled to begin on a new contract.

A grenade exploded Thursday night in Soviet Embassy premises in New Delhi but no one was hurt, the police said today. They said the grenade, which was apparently thrown into the residential area behind the embassy, damaged a door and some windows. The police quoted a Soviet diplomat as saying he had seen two people, including a Sikh, going past the building just before the explosion.

Poland's martial law authorities appear to be successfully pursuing a complex strategy that will allow them to lift martial law by the end of the year - thus mollifying international opinion -while at the same time stamping out the remnants of the Solidarity labor union and any other form of political dissent. The strategy balances highly visible gestures of conciliation, particularly toward the Roman Catholic Church, with a steely use of the powers of state, including a new framework of laws and the overwhelming deployment of masses of special riot policemen to make sure the populace stays in line. The North Atlantic Treaty Organization countries that imposed economic sanctions on Poland last February in response to the military takeover - a withdrawal of credits that has sorely hurt the already crippled economy by cutting off new hard currency loans to pay for imported parts and materials essential to the country's industry - set three conditions for lifting the punitive measures. These were the resumption of discussions with the Roman Catholic Church and the nation, the release of the Solidarity leader Lech Walesa and other detainees, and the end of martial law. At the same time President Reagan imposed sanctions against the Soviet Union, which were lifted last week while leaving in place those against Poland.

An official of the Polish Roman Catholic Church yesterday denied an NBC News report that Polish security agents, apparently in an attempt to discredit Lech Walesa, had presented church officials with tape recordings and photographs that showed the leader of the outlawed Solidarity union in ''sexually compromising situations'' with women. Asked about the NBC News report, which was made on Thursday, a spokesman for the Polish Interior Ministry, which oversees security matters, said, ''I know nothing about such plans.''

The Israeli Government today criticized remarks made by Secretary of State George P. Shultz, who said Thursday that a requirement for foreign teachers in the Israelioccupied West Bank to sign an oath disavowing the Palestine Liberation Organization was a ''problem of freedom, freedom of thought.'' The required Israeli statement has been a source of controversy here in the six months it has been in existence. It has so far resulted in the expulsion of at least 20 foreign teachers who refused to sign the form on the ground that it was politically biased. In addition, the teachers assert that when they applied for a work permit they signed a form agreeing to abide by the laws of Israel and that the form was therefore superfluous.

A report that Lebanese authorities have made their first arrests in their investigation of the massacre of Palestinian civilians here in September was distributed today by a local news agency close to the militias of the Lebanese Christian Phalange Party of President Amin Gemayel. The report, which was circulated by the Lebanese Central Information Agency but not supported by any other source, said that 12 suspects had been seized and that most of them were Moslem Shiites from southern Lebanon. The suspects were also said to include some southern Christians and one person who carried a Jordanian passport. Israel has said that Phalangists were responsible for the massacre, but the Phalangist-dominated militias known as the Lebanese Forces have repeatedly denied involvement. Maj. Saad Haddad, commander of an Israeli-supported militia in southern Lebanon consisting of both Christians and Moslems, testified at the official inquiry earlier this week that none of his troops had been involved in the killings.