St Trinian's/I Am Legend/The Kite Runner

Its hard not to enjoy the updated St Trinian's, there are so many jokes and not all of them are smutty

St Trinian's should be a disaster. Like the beloved film series of the 1950s and 1960s, it's set in an all-girl boarding school, where the supposedly wild pupils wear uniforms, play hockey and sell home-brewed vodka to a cockney spiv named Flash Harry (Russell Brand in George Cole's role). But within that anachronistic setting, the film tries painfully hard to be contemporary, and never shuts up about webcams and emos. It's also got Rupert Everett in drag, and Colin Firth having his leg abused twice by a dog named Darcy. By rights, it should be unwatchable, but St Trinian's scrapes through its Ofsted inspection by cramming in as many jokes as it possibly can, many of which have the gothic grisliness of Ronald Searle's original cartoons. You have to award a gold star to any film that pastiches Damien Hirst by pickling a schoolgirl in a fish tank.

Everett takes over from Alastair Sim to play both the headmistress and her brother, and seems to be impersonating Dame Edna Everage in the former part, Prince Charles in the latter. Firth parodies both his stuffed-shirt persona and his iconic wet-shirt moment while playing a government minister who plans to close the school. The teachers are far too shell-shocked to save St Trinian's themselves, so it's up to the pupils, led by Talulah Riley and Gemma Arterton, to raise funds by stealing a Vermeer from the National Gallery.

The film doesn't exploit the leering possibilities of schoolgirls in stockings and suspenders quite as much as its adverts do, but there are a few too many sex and drugs references, especially as they'll go over the heads of the pre-teen target audience. At least, I hope they'd go over the heads of the target audience. I had to have a couple of the double entendres decoded for me afterwards by more worldly critics from other newspapers. St Trinian's is nothing if not educational.

Released on Boxing Day, I Am Legend is based on Richard Matheson's novel, which has already been filmed twice as The Last Man On Earth and The Omega Man. And if it had come out 15 years ago, when the project was first mooted, those other two films would have been the ones to compare it to. Since then, though, 28 Days Later has become the decade's most influential horror/science fiction film, so "I Am Legend" now looks so derivative that it might as well be called 28 Months Later. In particular, the whole film is like a big-budget remake of the early sequence in 28 Days Later of Cillian Murphy wandering around a deserted London.

Inevitably, it's now set in a deserted New York. A plague has wiped out the human population, and the one man who's immune, Will Smith, passes the lonely hours by speeding along an overgrown Fifth Avenue in a sports car, and pushing through chest-high grass in Times Square, hunting deer. For three years, he's had this urban jungle to himself by day, but by night it belongs to the plague's other survivors, who have mutated into ravenous monsters. In Matheson's novel, they're traditional garlic-hating vampires, but in the film they're much the same as the mindless hordes in 28 Days Later, except that they can't come out in daylight.

It's not a very fresh scenario, then, but I Am Legend's vision of a desolate metropolis is impressive, as much in the small details as in the big picture. The most telling image isn't the empty streets; it's Smith strolling into his Washington Square home without needing to unlock the front door first. Towards the end, the film could have spent less time on speeches about God and Bob Marley, and more time on Smith fighting slimy cannibals, but for the most part I Am Legend is a scary, yet bravely sombre study of a man losing his mind. It's better than 28 Weeks Later, anyway.

Also released on Boxing Day, The Kite Runner is a moving, respectful adaptation of Khaled Hosseini's international best-seller, in which a Californian novelist remembers how he betrayed a loyal friend during his childhood in 1970s Kabul, and discovers how he can go back to Afghanistan and atone for that betrayal now. A drab central episode in America brings the film crashing down to earth, but the vibrant Afghan scenes are sweet and shocking by turns, and the balletic, CGI-assisted kite-flying is glorious.

In Alvin And The Chipmunks (U), three CGI singing chipmunks are lured away from their paternal songwriter (Jason Lee) by a scheming record company executive (David Cross). It's perfectly acceptable, as films cashing in on cartoons cashing in on novelty records go, but are children really crying out for a story about the cynical machinations of the music industry?