Each summer the range of movie offerings narrows as studios stick to their tentpoles and sequels and audiences continue to fade away.Before everyone completely forgets this summer’s forgettable movies, let me pose one final question: When did the movie virus set in? When did it become mandatory for the entire summer menu to consist of variations on “Charlie’s Angels”? It’s not as though the formula was working that well. Actual admissions declined in each of the past two summers as more and more filmgoers seemed turned off by the limited choice. Sure, “Finding Nemo” and “Bruce Almighty” were big hits in summer ’03, and one key reason was that they alone broke the formula. They weren’t “Bad Boys II” or “The Hulk.” They were more like summer movies used to be before tentpole mania gripped the business. Not that long ago, summer was the season when the widest selection of movies was in evidence. “Apocalypse Now” was an August movie in ’79. In summer ’84 filmgoers could feast on “Ghostbusters,” “Indiana Jones and the Temple of Doom,” “The Natural,” “Bachelor Party” and “Revenge of the Nerds.” As late as 1994, the summer fare encompassed “Forrest Gump” and “The Lion King.” Sure, “Speed” was a surprise hit, but lots of filmgoers opted for “The Mask,” “The Client” and even “Natural Born Killers.” It was not until 1996 that the virus started to become pervasive. That was the year when the four top movies all had the trappings of tentpoles: “Independence Day,” “Twister,” “Mission: Impossible” and “The Rock.” Efforts to break the mold that year did not pan out — remember “The Cable Guy” and “Tin Cup”? And suddenly everyone began to wonder: Why even try for something different when formula action is a sure thing? It wasn’t, of course. “Speed 2″ was a disaster. The “Batman” franchise imploded. Occasional sleepers like “The Blair Witch Project” kept challenging the conventional wisdom, but they were dismissed as bizarre deviations. As late as 1998, the tyranny of the tentpoles was still in doubt. Big marketing bucks were lavished on two pretty dreadful blockbusters — “Armageddon” and “Godzilla” — but the studios managed to slip some surprises into the summer schedule. They included “The Truman Show,” “Bulworth” and, of course, the formidable “Saving Private Ryan.” Toward summer’s end, when everyone was supposed to be buying tickets to “Lethal Weapon 4,” the hottest movie in town was the ultimate sleeper: “There’s Something About Mary.” The lessons of 1998 should have been clear. Surprise your audience. Keep filmgoers a little off-balance. Well the lessons were ignored. Why go for a “Private Ryan” when you can replicate “Lara Croft”? The upshot for 2003 was a rather blah summer. Though a 7% rise in ticket prices helped pump up total grosses by 2%, actual admissions were down. Thanks to “Nemo” and “Pirates of the Caribbean,” Disney managed to capture the market share crown from Universal — the first time in a few years that the troubled Mouse House has won the title. Now with summer’s end, the marquees already are displaying a bolder array of titles. Some of the early fall films represent the customary mixed bag of losers and rejects — movies that need a quick theatrical run before being consigned to video heaven. But here and there one can find some interesting sleepers, possibly even Oscar grist. Given the shortened Academy season, some normal December releases have been pushed up by a few weeks. But will adult filmgoers end their hibernation and embrace these new movies? Will the movie habit assert itself again despite a summer of turnoffs? After a summer of “Charlie’s Angels,” can “Cold Mountain” come out of the cold? The “virus,” one hopes, will not prove to be a year-round affliction.