My son's open house was last week. It was standing room only! We also had to schedule our parent teacher conferences that will be held in December by signing up on a sheet she had posted. I was lucky I got there when I did, because I ended up with the last evening appt. at 7:45. I noticed that all of the evening appts. were taken and that only one person signed up for a day time meeting. I think most parents are working during the day, so a day time open house or meeting is not going to work for them.
Also, I did get a personalized thank you note from the principal of the school thanking me for taking the time to go to the open house. It was a photocopied note with my name handwritten by the teacher, but I thought that was a really nice thing to do!