At a year-end forum the glitterati shine and trade their latest ideas

When a conservative think tank gives a Christmas party, what does it look like? For the Washington-based American Enterprise Institute it is four days of deck the halls with public-policy forums, panels, dinners, and speeches. Each December, for about a week and at an approximate cost of $125,000 (participant fees providing most of the money), the institute throws the intellectual equivalent of a conservative tour of Santa's workshop. Its most prestigious thinkers as well as invited national figures air the policy issues they've been tinkering with all year.

Topics this year will range from ''the economy in deficit'' to an analysis of the November elections, as well as United States-Soviet relations. President Ford (an AEI fellow) and former Australian Prime Minister Malcolm Fraser will cover a wide range of issues on foreign relations; Jack A. Meyer, director of health policies at AEI, will report on a recent visit to Europe, where he conducted an analysis on what is done for the elderly, and what it costs. Theologian Michael Novak will discuss the US economy in light of both his own AEI-funded book, ''The Spirit of Democratic Capitalism,'' and the forthcoming Roman Catholic bishops' pastoral letter on capitalism.

Another luminary with AEI connections is Judge Robert H. Bork. A former AEI fellow and member of its council of academic advisers, Judge Bork, according to knowledgeable insiders, is a likely candidate for a Supreme Court berth in a second Reagan administration.