"With the right product, there is basically no ceiling to business," said Daily Variety this week, and that's certainly the lesson that's being suggested by moviegoers these days.

So far, 1987 has been an exceptionally good year for business -- and last week, the total box office grosses simply went through the roof, with six films topping the $4 million mark, four films making more than $7 million, and the top 10 movies bringing in almost $50 million, which is $15 million more than last year's totals for the same week, and $8 million more than the year before that. The only year in which early-summer business was better, in fact, was 1984 -- when "Ghostbusters," "Indiana Jones and the Temple of Doom," "Star Trek III" and "Gremlins" were showing.

The big winners this year include two minor surprises -- Arnold Schwarzenegger's "Predator," which was hardly expected to beat "Beverly Hills Cop II" as roundly as it did, and "The Witches of Eastwick," which had by far the best per-screen average -- and two still-strong holdovers, "Beverly Hills Cop II" and "The Untouchables."

Last weekend's business, in fact, included two of the four biggest openings of the year: "Predator's" total was the year's second-biggest opening, trailing only "Cop," while the "Witches" total was 1987's fourth-biggest, behind those two films and "Untouchables." "The Believers," meanwhile, couldn't stand up to the competition in its first week -- but on the other hand, "Harry and the Hendersons" improved on its opening weekend totals despite the new competition.

The Desert of 'Ishtar' Clearly not tenacious is "Ishtar." Columbia Pictures officially gave up on the big-budget conversation piece over the weekend: the studio is no longer reporting the movie's grosses, a sure sign that they are negligible. Before it stopped counting, "Ishtar" had earned about $13 million -- less than the total salaries of Warren Beatty, Dustin Hoffman and Elaine May.

Luring the Filmmakers The Common Market countries in Europe are considering a plan under which they'd provide interest-free loans up to $50,000, to cover half the cost of low-budget films shot in those countries ... And in Canada, 1989 has been declared Canada Film Year. Buoyed by the response to recent Canadian films like "Decline of the American Empire" and encouraged by the success of the recent British Film Year, the Canadian year will coincide with the 50th anniversary of the National Film Board of Canada. The year will be designed to showcase Canadian products -- and also to lure back Canadian filmmakers who've headed to the United States, even though the trend of late has been for U.S. moviemakers to save money by shooting in Canada.

Odds and Ends Max Youngstein, a one-time vice president at United Artists, has formed his own production and distribution company; he's calling it Artists United. United Artists was named for its founders: Charlie Chaplin, Douglas Fairbanks, Mary Pickford and D.W. Griffith; no word on what artists Youngstein is talking about ... Director Franco Zeffirelli says he's signed Elizabeth Taylor to play opera singer Nadina Buliscioff in his upcoming film biography of conductor Arturo Toscanini ... The romantic comedy "Boy Rents Girl" has changed its name to something subtler: "Can't Buy Me Love." Rights to the August release were recently acquired by Touchstone Pictures, and the Disney-owned company thought "Boy Rents Girl" sounded sexist. So they gave it the new title and paid what is reportedly an exceptionally large sum of money (to Michael Jackson's publishing company) to use the Beatles' performance of the title song, which the band debuted 23 years ago in "A Hard Day's Night."