I love having you over, even though it is a lot of work for me. I guess there is additional benefit (besides your great company) for me in getting my house clean for the event, however!
Please ask for or get more food or refills if I am stupidly negligent in asking at the right times. Please use the guest towels I put out in the bathroom for you; that is what they are for. If you don't care for something, don't feel obligated to eat it - life is too short and I want you to enjoy your visit in my home.
Now the other side....
If we are eating at the table, please pass the food. Don't let it accumulate around you after you fill your plate. The rest of the guests would like some, too!
If it is late and I am clearly fighting gravity and repeatedly almost sliding out of my chair, please go home! I had fun, but I'm pooped!
Don't offer to help clean up. It's next to impossible to help in a strange kitchen. I appreciate the thought, but that's not why I invited you; you don't have to work for your dinner, and it's faster if I do it myself. Maybe I will even do it tomorrow, ha.