Social Contracts

I'm putting together the documentation for some of my courses next year, and I'm trying to be very clear about what will be expected from students on a week-by-week basis (and what they can expect from me). I started writing down some things like You are expected to do the reading, you are expected to show up, you are expected to speak up in class, you are expected to respect your peers and not be homophobic/racist/transphobic/etc, and it occurred to me that some of you people reading this might have done this before and have some suggestions - do you have contracts or ground rules for seminars? What are they? Are they helpful?