What was going on when I was born?

NOW that the Marriott Corporation has bowed out, the search is on for someone to manage Playland, the financially troubled county amusement park in Rye, until its future is decided. Plans for next summer remain uncertain as the county, with Marriott's help, begins a recruiting drive among amusement-park professionals to take over management ''on a one-year contract basis'' while a controversial draft master plan is readied for public hearings and legislative approval. Last week, County Executive Alfred B. DelBello announced that Marriott's management role would cease with the expiration of its two-year contract on Dec. 31. The decision, Mr. DelBello said, was ''mutual.''

Skeptics, be quiet. George Washington not only slept at the Roe Tavern in East Setauket, L.I., on April 22, 1790, he even gave it a review.

The United States, seeking to avoid a political rift in the Atlantic alliance, has dropped its refusal to resume negotiations in Madrid on East-West cooperation. The Reagan Administration had declined to resume the Madrid talks with the Soviet Union because of the continuing crackdown in Poland. But the Americans have now won allied consent to make any East-West accord conditional on the Russians accepting and living up to such measures as allowing free trade unions and ending radio jamming. A senior Administration official said today that the American willingness to resume work on a final Madrid document was more tactical than substantive. He said it was inconceivable to the Administration that the Russians would accept the terms that would be laid down by the NATO alliance, or that any document would be approved.

KEEPING FAITH Memoirs of a President. By Jimmy Carter. Illustrated. 622 pp. New York: Bantam Books. $22.50. Jimmy Carter's term as President was essentially an interregnum, a bridge that carried the country from the end of its preoccupation with Watergate to the advent of the Reagan revolution. The man from Georgia arrived in Washington in January 1977, an out-sider who had confounded the political odds by getting elected in the first place. He left it four years later, still largely an outsider, after a stunning electoral defeat in which he lost 44 of 50 states. ''Keeping Faith,'' his personal account of those four years, is vintage Jimmy Carter, a mirror, in fact, of its author: honest, sincere, intelligent, dry, humorless and impersonal. There is little introspection in its pages, even less analysis of why and how things happened.

When a Federal agency tried to end rent stabilization at the Lincoln Towers complex in Manhattan about five years ago, it reckoned without the influence of Shirley Quill. The president of the Towers Tenants Association, she had been a labor organizer before she met her husband, Michael J. Quill, the late president of the Transport Workers Union. Mrs. Quill responded to the Federal threat by organizing an intensive lobbying campaign and an outdoor rally of the Towers' 9,000 tenants.

THAN-EXPECTED turnout across the state and lopsided Democratic pluralties in Essex and Hudson Counties were two of the keys to the victory of Frank R. Lautenberg, Democrat of Montclair, over Representative Millicent Fenwick, Republican of Bernardsville, in the race for United States Senate. The voter turnout in 20 of the state's 21 counties was higher than in the 1978 contest between Bill Bradley of Denville and his Republican opponent, Jeffrey Bell of Leonia, despite expectations that it would be about the same. More than 58 percent of the state's registered voters went to the polls last Tuesday, compared to a little less than 54 percent four years ago. The only county with a turnout lower than in 1978 was Hudson, but the organization there outdid itself in getting out the vote for the 58-year-old Mr. Lautenberg.

THE causes of the population loss shown in the 1980 census appear to be easing more rapidly than expected, according to a report to be released this week by the county's Planning Department. The report, which examines in detail the changing profile of the county's population in terms of age, sex and ethnic background, concludes that ''Westchester County's population level will probably bottom out and begin to slowly grow again before the rest of the tri-state region, which was also affected, stabilizes and rebounds.'' ''We're reaching an equilibrium stage,'' said Albert A. Annunziata, the Planning Department's director of research, who drafted the report, the second in a series analyzing data in the 1980 census. ''We're at a period where we are catching our breath from the tremendous population growth of the 1950's and early 1960's.'' Referring to the drop in population to 866,599 in 1980, from 894,104 in 1970, Mr. Annunziata said, ''We probably needed that decline as an adjustment phase.''

The Koch administration, which has already imposed a hiring freeze and ordered spending reductions in each municipal agency, must take additional ''stringent'' measures to balance New York City's budget, the State Comptroller's office said yesterday. The Comptroller's office said that there had been unexpectedly large reductions in business tax revenues and that the city's fiscal outlook had worsened significantly in the three weeks since the office warned that revenues for the current fiscal year would be $136 million below projections. Shortfall Put at $206 Million The latest report estimates that revenue will fall short by about $206 million. It said the $70 million difference was largely the result of sharp and sudden declines in collections of the general corporation tax, down $35 million, and the financial corporation tax, down $30 million. It attributed those declines to the sluggish economy.

Buoyed by an errorless defense and a bit of offensive trickery, Notre Dame stunned previously-unbeaten Pittsburgh, the top-ranked team in the country, 31-16, today before 60,162 fans at Pitt Stadium. The Panthers, who last week held the No.1 position in both of the nation's wire-service polls and The New York Times computer rankings, saw their record fall to 7-1. The Irish, ranked No. 20 by United Press International and unranked by The Associated Press and by The Times, improved their record to 6-1-1. A strong defense and numerous errors by Pittsburgh helped Notre Dame stayed in contention going into the final period. Trailing by 13-10, they rallied to score 21 points against a team that had allowed an average of 10 points a game.

Members of Congress from both parties are trying to devise a job program to deal with unemployment, now at the highest point in 42 years. Senators and representatives of both parties said the results of the midterm elections seemed to indicate a public desire for the Federal Government to play a larger and more active role in combating unemployment. President Reagan, who has long opposed such programs on the ground that they provide only short-term help while increasing inflation and Federal deficits, said today in a radio address that there was no ''magic method'' of adding jobs. (Page 32.)

JUST a few years ago, if you wanted a second mortgage and you lived i n New York, you went to Connecticut. New York law discouraged l enders from giving second mortgages, but determined borrowers could w ork through companies like Grammatin Investors Corporation, a p rivate finance company with offices in Queens. Grammatin would pick you up in a car and drive you to Connecticut. Then Grammatin, in conjunction with a Connecticut bank, would draw up the papers for your second mortgage. You had to be creditworthy, of course, but Connecticut's law made it advantageous for lenders to provide second mortgages.

NORWALK WHEN two census tracts in the heart of South Norwalk were designated recently as one of six enterprise zones in the state, Roderick Johnson, executive director of the Norwalk Redevelopment Agency, called it ''a real shot in the arm for Norwalk's redevelopment project.'' The area of the enterprise zone - roughly a square mile in the most rundown part of South Norwalk, where prostitution, unemployment and crime have been constant problems - has long been a target for renewal. A redevelopment plan, a joint effort by the City of Norwalk, the redevelopment agency and a private concern, has been on the books since 1978. But while the first phase of the plan has been under way for a year, the success of the redevelopment project, one of the most extensive and ambitious ever proposed in the state, had been viewed by many people in local government as dependent on the financial incentives provided by enterprise zone status. With the designation early last month by the state's Department of Economic Development, hopes have been buoyed for the project. Now the agency must raise about a quarter of a billion dollars over the next 10 years from Federal, state, city and private sources.