Ground Rules
First a few ground rules to make sure unacceptable behavior is clearly described in advance.
1. Don't be a jerk. This is a lighthearted game that's intended to be fun for everyone. The old golden rule is a good general principle. As is "don't say something if you can't say something nice". As is "When in doubt, just don't say it."
That's a little vague, so some specifics:
2. Racism, sexism, genderism, etcism won't be tolerated
3. No politics This is one of my escapes... please don't drag the real world into it.
4. Don't correct others If a correction needs to be made, I'll PM the person(s) involved. Everyone hates to be negated, even by the GM. Unless it's something incredibly egregious that would more or less kill the game, I will most likely leave whatever it is as is and ask for something different next time.
5. If you mess up, apologize We all make mistakes. No need to sacrifice yourself on the altar of dignity, but do own up to it and make it right.
6. Have fun. Don't take anything too seriously. This is an escape.