I agree with decorating the teachers' classroom! Maybe throw a surprise party? I like to get my teachers little gifts like chocolate, little notes, or even a Starbucks gift card because a lot of teachers like coffee. Even a tiny compliment could make their day.
Call me old fashioned, but my guess would be a hand written note telling them why you think their special, would be more then enough to make their day...Special.
Represent the all teacher in your school and tell something about teacher qualities .You can enjoy with your inspired teacher.
Make a presentable celebration. http://funadvice.com/r/168fdil24ou
Decorte staf room,sing a song 4 teachers n giving sum gift to fav teacher etc....