T.H.
Maybe...
You do such a wonderful Job-ble, Come on in and Gobble, Gobble!
Also, to go off Tracy's answer...if you have the time it would be kind of fun to go around the school and ask students, staff and other teachers what they appreciate about the school or specific departments or even specific people. Then type them up and put the person's first name (or just the statement) below it. Print them out on colorful paper, cut them apart and sprinkle them around the table for people to read as they dine. It would be personal and wouldn't take a ton of time or effort!