Every summer schedule has a few unknown quantities and among this year's is a handful of films that look intriguing on paper and may perform in the marketplace.

Dark horses with mainstream label studio distribution include Disturbia, which Paramount/DreamWorks will open in the US on April 13 but which Paramount Pictures International (PPI) is opening in many international markets in May and June. 'We think it's got very, very big potential,' says PPI's Andrew Cripps.

The busy Shia LaBeouf stars as a troubled teen who thinks his neighbour may be a serial killer.

Warner takes a big gamble with Lucky You, opening the Curtis Hanson-directed drama on May 4 opposite Spider-Man 3. Drew Barrymore, Eric Bana and Robert Duvall star in the story of a professional poker player and his girlfriend. Warner Bros Pictures International will use the film to counter programme against blockbusters in the international marketplace through May and June.

New Line's Hairspray, which opens domestically on July 20, is a screen version of the successful Broadway musical adapted from the 1988 John Waters movie about 1950s Baltimore teenagers. John Travolta stars - in fat suit and drag - and Adam Shankman (Bringing Down The House) directs.

Grease is the word for Hairspray
Though the film may be a tough sell in international markets that have not yet seen the stage show, New Line is still optimistic, says international president Camela Galano. 'We compare it to Grease, rather than Dreamgirls or Chicago,' she says. 'It's fun, the music is great, it has wonderful costumes and it's a great period.'

Specialty label summer films that could break through include Focus Features' mother-daughter drama Evening, with Vanessa Redgrave and Claire Danes starring for director Lajos Koltai (Fateless). Toni Collette, Natasha Richardson, Glenn Close and Meryl Streep also feature. The drama opens in the US on June 15, opposite the Fantastic Four sequel.

Also from Focus is Atonement (August 31 in the US), an adaptation of Ian McEwan's bestselling novel starring Keira Knightley and James McAvoy (an actor with several films set for release this summer) and directed by Joe Wright (Pride & Prejudice).

Paramount Vantage's A Mighty Heart, which opens on June 22, opposite Evan Almighty, is based on the abduction and execution in Pakistan of Wall Street Journal reporter Daniel Pearl. Angelina Jolie, Dan Futterman and Archie Panjabi star for writer-director Michael Winterbottom.