AMONG the nominations for the Oscars next month are two screenplays that are so sublime - both in execution and philosophy - that I would like to think they mark not only a new trend in American film-making but also a new trend in American thinking. The surprise, humour and satisfaction of Lars And The Real Girl (which opens in March) and this week's Juno lie in the fact that they present situations in which people would be expected to act stupidly and badly, and yet they allow their characters to act wisely and well. It sounds simple, but to pull this off in our oh-so-cynical world represents, for each film, a major comic achievement.

JUNO Click here to see more film trailers

JUNO DIRECTOR: JASON REITMAN RATING: Juno MacGuff (Ellen Page) is a 16-year-old Minnesota schoolgirl who, the first time she sleeps with her not-quite-boyfriend Bleeker (Michael Cera), accidentally conceives. Cue chest-beating family melodrama? Not so. Faced with the unwanted pregnancy and accepting that "I'm in high school. I'm ill-equipped," Juno decides calmly to have the child and then find it adoptive parents.

The girl's preternatural wisdom and presence of mind are refreshing and unexpected. So too are the reactions of her father and stepmother (JK Simmons and Allison Janney), the sort of cool parents one can only dream of, who quip that they might have preferred Juno on hard drugs than pregnant, then without further ado lend their unequivocal support. Recognising that Juno's scenario requires a little friction, writer Diablo Cody provides it courtesy of the adoptive couple: the intensely broody Vanessa (Jennifer Garner) and her husband Mark (Jason Bateman), with whom, in her only lapse in judgement, Juno becomes friends.

The film's unusual tone is accompanied by an inimitable style. Director Jason Reitman has commissioned an inspired stop-motion animated title sequence, which establishes Juno as an attitudinal free-spirit. He creates a colourful, breezy milieu, complete with quirky soundtrack, in which to place his heroine. The whole has a fable-like air that reflects Cody's message about individual choice over societal pressure, calm over hysteria. The cast is magnificent, but the laurel has to go to Page, who confirms the promise of her vigilante in Hard Candy with a much more wholesome creation.

THE DIVING BELL AND THE BUTTERFLY Click here to see more film trailers

THE DIVING BELL AND THE BUTTERFLY DIRECTOR: JULIAN SCHNABEL RATING: The Diving Bell And The Butterfly is a beautiful, heart-rending film, and an experience that leaves us with a humbling sense of our mortality. Based on the book by the French journalist Jean-Dominique Bauby, it charts Bauby's experience and reflections following a stroke that left him totally paralysed, save for the control of his left eyelid. One moment Bauby was leading a glamorous, successful and healthy life; the next, as the name of his condition, "locked-in syndrome", suggests, in hellish imprisonment, an active mind trapped within his own body.

One might wonder how cinematic a story about a man confined to a hospital bed can be, particularly if he cannot even speak. But artist-turned-filmmaker Julian Schnabel sees this not as an obstacle, rather as a spur to a poetic rendering of his subject's story. Much of the film is seen through Bauby's one, watering eye, as faces peer into his, and light and colour make often abstract impressions. As Bauby, Mathieu Almaric somehow maintains the contorted visage that Bauby described as "looking like I came out of a vat of formaldehyde". His interior dialogue, as voiceover, describes the claustrophobia that he likens to being trapped in a diving suit, underwater.

His one outlet is the laborious communication system devised by the hospital staff, in which he blinks to halt their procession through the alphabet, letter by letter, to construct sentences. As Bauby starts to compose a book, Schnabel moves away from his point of view, to that of the women in his life - his estranged wife, his lover, the speech therapists. Meanwhile, flashbacks show him as the man he was, his relationship with his aged father (Max Von Sydow) and the children he regrets not knowing more. The result is a reflection both on how to live life and on how to cope when your life goes off the rails. It's quite overwhelming.

NATIONAL TREASURE: BOOK OF SECRETS Click here to see more film trailers

NATIONAL TREASURE: BOOK OF SECRETS DIRECTOR: JON TURTLETAUB RATING: The second outing for Nicholas Cage as treasure hunter Ben Gates, National Treasure: Book Of Secrets confirms Gates as a very second-rate Indiana Jones. No hat, no bullwhip, no attitude, no Nazis and no Spielberg at the helm. The first sort of worked; the reprise, which has Gates trying to clear his ancestor of conspiracy in Lincoln's assassination, really doesn't. As Gates's mum, Helen Mirren merely looks embarrassed.

DEFINITELY, MAYBE Click here to see more film trailers

DEFINITELY, MAYBE DIRECTOR: ADAM BROOKS RATING: Definitely, Maybe, produced by the romantic conveyor belt of Working Title, benefits hugely from a leading man whose names do not include Hugh, Grant, Colin or Firth, and a setting - New York during the Clinton years - that lends a mood of tarnished promise that feeds into the romance.

On the eve of his divorce, 30-something Will (Ryan Reynolds) is questioned by his 10-year-old daughter about his love life before marriage. They play a game: Maya (Abigail Breslin) wants to hear about Dad's loves, whom he will give fictional names, and she will guess which one ended up to be her mother. Since we ourselves have not seen the woman, we too have to guess. And of course in reflecting on his old flames, Will realises that he is still in love with one of them.

The trip down memory lane takes in the hometown love (Elizabeth Banks), the dazzling urbanite (Rachel Weisz) and the "best friend" (Isla Fisher). In the meantime, we see how Will changes from an idealist working in the Clinton presidential campaign to a sell-out ad man. The characters are appealing and nicely restrained, and it's well written by director Adam Brooks - sharp and sweet without an iota of the manipulation that Richard Curtis brings to his films.