What is this up-coming horror movie called?

I was visiting California and went to the AMC theater to see Be Kind Rewind, but before it I was enjoying some really great previews. There was one which looked like a HORRIBLE movie because it was so gruesome and bloody. I don't remember anything about the actors or the title, but it was about this family of three being terrorized by two young guys. One looked similar to Lucas Grabeel. The woman being terrorized looked similar to Keira Knightley or a blonde Natalie Portman. The two guys (including the one that looked like Grabeel) were whacking and tripping the family with golf clubs. There was one part where one of the men said to the family, "Let's make a bet. You bet you will be alive tomorrow, we bet you won't." Or something of the sort. I think it comes out in 2008. My best friend would be very interested with this movie and I want to find out what it is for her! Does anyone know?