Superbad (15)<br/>Shoot 'Em Up (18)<br/>The Serpent (15)<br/>December Boys (12A) Obscene and not nerds

From the same stable of bad-taste comedy with heart as the recent Knocked Up, Superbad is less ambitious but far funnier. After an uneasy opening 10 minutes of lewd teen talk, it settles into a hilarious and poignant account of school outcasts struggling to conform, without realising that no one is quite as cool as they are. This gives nerds, at best patronised in movies, genuine cause for self-esteem.

Jonah Hill and Michael Cera play, respectively, overweight and sex-obsessed Seth, and smart but shy Evan: an odd couple, bonded by a shared alienation from the high-school herd. But there is simmering discontent between them, as Evan has won a place at a better college than his friend and, worse than that, plans to room with the even more peculiar Fogell (Christopher Mintz-Plasse).

Matters come to a head during an eventful party night – the lads' last bid to lose their virginity before going up a grade. After carefully dressing ("No one's got a hand job in cargo shorts since 'Nam," protests Seth), they head out with Fogell's false ID to find liquor.

Seth Rogen, who starred in Knocked Up, co-wrote the script for this when he was 13 (one assumes "Seth" is a tad autobiographical) and has enormous fun playing one of two comedy cops, who ought to be arresting the under-aged drinkers but instead contribute to their riotous and rewarding rite of passage. The title and opening credits sequence evoke a Blaxploitation vibe, mixed with a little Starsky and Hutch – reminding us of the thin line between being hip, and totally naff.

The Superbad boys would probably love Shoot 'Em Up, a gleefully preposterous action film, soaked in bad jokes, sexism and comic-book violence. It's so over the top, that it makes the offerings of Tarantino and Robert Rodriguez seem like models of restraint.

Clive Owen plays sexy and indestructible Mr Smith, who takes on Paul Giamatti's army of hoods in defence of a baby he's just delivered during a shoot-out. Smith is a very angry fellow, who will blow the back of a man's head off if he's wearing a ponytail, and is a dab hand with a carrot in ways that will make you wince. Put a babe in his arms, though, and he's mush.

It's tosh, of course, made watchable by inventive action and its slumming thesps. Long touted for 007 before Daniel Craig won the role, Owen shows us what we've missed. "Bond, James Bond" just doesn't compare with "I'm a British nanny. And I'm dangerous."

A more mature thriller, from France, The Serpent concerns a photographer (Yvan Attal) whose life is a mess of divorce and child custody, even before a shifty former classmate (Clovis Cornillac) pops up to avenge a childhood cruelty. Blackmail, murder and mental torture ensue, to gripping effect.

December Boys is an extremely bland tale about four orphans competing for potential parents in Sixties Australia. Daniel Radcliffe confirms that his awkwardness hitherto is nothing to do with Harry Potter's character, but his own. He's as stiff as a board here, until the melodrama – like Voldemort – pushes him to act.

Nicholas Barber is away