The film, written by acclaimed playwright Daragh Caville, focuses on three teens who set out for a wild weekend of drugs, sex and crime only to see it escalate into something far more serious than they imagined. It co-stars relative unknowns Robert Sheehan and Kimberley Nixon, and is set for release next year.
While Daniel Radcliffe has tried more extreme methods of branching out (mainly by taking that infamous role in Equus, which is coming to Broadway per the above link) and Emma Watson hasn't done very much at all (she voices a character in this year's The Tale of Despereaux, but that seems to be it), Grint has spent what spare time he has toiling away in indieville. Cherry Bomb was preceded by the reasonably well-received and much less racy Driving Lessons, about a troubled boy's friendship with a retired actress.
It's already so hard for child actors to make a successful transition into adult careers, but it's harder still for actors who are inextricably identified with particular roles. Of the three Potter kids, Grint looks the least like a movie star -- which could wind up being good or bad. In his case I think indie films and supporting roles are the way to go, so he's doing it right.
[hat tip: Cinema Blend]