No Strings Attached (2008)

Two apathetic guys with nothing but time on their hands agree to housesit for a friend in a less-than-stellar neighborhood. During their time there, they witness a murder in the backyard and are drawn into a cat and mouse game where they must outwit an assassin and a gang of mob enforcers, and somehow escape unscathed before their friend's family from out of town stops by to visit.