What is "hack!"

'Hack! ' is a 2007 American horror film directed and written by Matt Flynn. The film centres on a group of students who, while on a field trip, become victims in a snuff film, and stars Danica McKellar, Jay Kenneth Johnson, William Forsythe, Sean Kanan, Juliet Landau, Justin Chon, Travis Schuldt, Adrienne Frantz and Gabrielle Richens. The film was released in the UK on July 20, 2007 before receiving a US release on December 11, 2007.