It's interesting to see Adam Sandler tinker with his remarkably successful formula with the care and precision of a medieval theologian, mixing and sorting his ensemble cast of regulars, adjusting his lead character's admixture of likability, impulse control issues, and inherent appeal to his leading lady. He is a peculiar combination of Woody Allen, Benny Hill, and Bill Murray.

Most appealing and chemically compatible of Sandler's babe parade has been Drew Barrymore (The Wedding Singer), whose blend of vulnerability, goofy sensuality and romanticism interlaces well with Sandler's similar appeal.

In 50 First Dates, which is very little like the slapstick farce implied by the film's title and marketing campaign, Sandler is a vet at a Hawaiian Sea World-type aquatic park - requisite rapport with his anthropomorphized mammalian charges signaling in shorthand his character's inherent goodness despite his systematic harvesting of hot female tourists at the penultimate moment of their visits, thereby assuring himself a steady supply of stringless tang.

But then he encounters Drew's fresh-faced character in a quaint local diner, building an elaborate architectural model out of waffles - which apparently evidences both her quirkiness and artistic acumen - and is smitten en toto. One small problem: blatantly incorporating both Groundhogs Day and Memento, we learn that Drew has severe short-term memory loss, brought on by a car accident of about a year past, and can't acquire new memories that last beyond the day at hand. She wakes up every morning thinking it's the same day, an impression her father (Blake Clark), brother (Sean Astin, with a strange lisp and roid-driven body-building fixation), and the denizens of the diner perform elaborate rituals (hundreds of copies of the same day's newspaper, celebrating the father's birthday, etc.) to perpetuate.

Enter Sandler, sand in their well-oiled machinery, who refuses to be deterred by Barrymore's complete lack of recognition of him from day to day, and the unpredictability of her response to his daily "courting" (the old-fashioned connotations of the word are apt).

Rather than play this absurdity for easy laughs, though (leaving those to side characters llike Rob Schneider, in full-on native Hawaiian guise), Sandler and Barrymore quite poignantly convey some of the genuine emotional and practical implications of their predicament, and very unexpectedly forgo an easy happy ending as well.

50 First Dates is much more emotionally complex and thoughtful than it had to have been, its sweetness adumbrated by moments of real depth, and that is a very pleasant surprise.