Create a retreat for the teachers during one lunch period. In addition to the lunch itself, hire someone to give the teachers a chair massage. Set the mood with soft music and scented candles, and give the teachers a small plant or flower to take home with them. If teachers normally need to eat with their students, arrange for volunteers to do this in order for the teachers to get a real lunch break at school.
Prepare a formal lunch at the beginning or the end of the school year and pay for a motivational speaker to come and speak to the teachers. The speaker could be humorous or share transformational stories about teachers. The school district, rather than the PTA, generally provides this type of lunch because of the expense.
Teachers accomplish a lot on teacher work days. Providing a catered meal for the teachers on these days goes a long way. The teachers don't face the pressure of returning to the classroom, so they can talk more leisurely to each other. The catered lunch also makes life easy for PTA volunteers. The caterer does the set-up and clean-up, allowing parents to spend that time with their children at home.
A letter of appreciation from a student is easy to keep in a folder or scrapbook, and the sincere thank you lets the teacher know the value of her work. Ask PTA workers and homeroom representatives to send a letter home asking parents to have their children write a thank you letter to a teacher, and deliver these at the lunch. Students can also be the servers, and they can arrange to put on a short program for the lunch. Ask for student volunteers to perform music and skits for their teachers.