School festivals
Some preschools organize school festivals where parents hold bazaars, have stands selling festival foods such as yakisoba (stir-fried noodles), and operate booths with games for the children. At most preschools, representatives of the Parents' Association are mainly responsible for organizing the festivals. After one of these festivals, you may write about your impressions and express your appreciation. You may of course speak to the teachers or Parents' Association representatives directly instead of writing in the renrakucho.
You may choose whether or not to thank the school for the event. You may also choose to make just a single comment regarding your impressions and/or your child's attitude.