Finally, an Adam Sandler movie that cuts directly to the heart of his appeal: repetition and brain damage. To enjoy “50 First Dates,” you better suffer from some form of memory loss, because it’s the same tired tripe — albeit kinder, gentler tripe — that the comedian has been serving the public for years under his odious Happy Madison production banner.

Granted, Sandler — as Hawaii marine park veternarian Henry Roth — is no longer the hot-tempered brawler he usually plays, but he does have that one, all-important compulsive tendency. Specifically, Henry will sleep with anything that moves: beautiful women, homely women, young women, old women, men — each of them comes to Hawaii looking for a fling, which Henry provides, along with a cock-and-bull story about being a secret agent or a cliff diver or anything that will facilitate seduction. Afterwards, Henry acts aloof and irritated, and sends them packing.

Henry must be a real dipstick, right? Wrong. He is, in fact, a totally great guy. Duh, he’s Adam Sandler! He lives under an aquarium and high-fives his walrus and is paid frequent, funny visits by his native buddy Ula (Rob Schneider) and a chattering gaggle of cute little Hawaiian kids who adore him. What’s not to adore? His taught his walrus how to vomit on cue!

It turns out that Henry’s warped love life is really no big deal, just some clever prep work invented by director Peter Segal (“Anger Management”) and writer George Wang to pave the way for Lucy Whitmore (an appealing Drew Barrymore), a local art teacher who suffered a brain injury that prevents her from retaining her daily memories, thus making her the ideal ironic counterpart to the conquest-oriented Henry. Every morning Lucy wakes up thinking it’s the same day in early October when she had her accident, and every day Henry has to conquer her anew.

I’m almost ashamed to admit it, but there is something sadly, tuggingly romantic buried under the surface of “50 First Dates,” though ultimately it has very little to do with Sandler’s character. It has to do with Lucy’s gruff ex-Navy father (Blake Clark) and dopey, steroid-enhanced brother (Sean Astin, funny but miscast), who go to elaborate lengths to preserve Lucy’s happiness and peace of mind. Every morning they put out the same back issue of the Honolulu Advertiser, watch the same taped football game and feign surprise at the twist-ending in “The Sixth Sense,” all so Lucy won't have to confront her handicap, clinically known as anterograde amnesia. Their lives basically become an exhausting hybrid of “Groundhog Day” and “Memento.” Life is stranger than fiction, in this case — such people do exist.

Against everybody’s wishes but his own, lovesick Henry interjects himself into this precarious routine and figures out a way to have a halfway normal relationship with Lucy: he makes a videotape that crisply summarizes her life after the accident and shows it to her every morning when she wakes up. Suffice to say, Lucy always manages to confront her misfortune with an unbelievably cool head — so unbelievably, in fact, that her subsequent love affair with Henry, and the numerous “first kisses” that follow, smack of some serious bull doody.

Fans of “The Wedding Singer” — arguably Sandler’s funniest movie — will probably be all a-twitter to see him paired up with Barrymore again, but there’s one little problem: “50 First Dates,” unlike “The Wedding Singer,” was produced by Happy Madison. Observe how uncannily Sandler’s Happy Madison movies tend to suck (“Mr. Deeds,” “Little Nicky,’’ “The Waterboy”) and how uncannily the others tend not to (“The Wedding Singer,” “Punch Drunk Love,” “Anger Management”). It’s almost scientific.

Consequently, “50 First Dates” is packed with the usual crud: the buttcrack jokes, the idiotic cameos by Sandler’s business partners (including executive producer Allen Covert as somebody called 10 Second Tom) and “Saturday Night Live” cohort Schneider, who is tolerable until he starts using phrases such as “Waikiki sneaky between the cheeky.”

As if that isn’t heinous enough, there’s the once-great Dan Aykroyd as Lucy's neurologist, cracking wise about J. Edgar Hoover. J. Edgar Hoover? Looks like Lucy isn’t the only one living in the past.