Have the students put chairs in a circle, with one less than the number of students. The student left standing has to ask the others a question i.e. Are you wearing glasses? If the answer is yes, then the students with glasses have to stand up and quickly switch chairs, giving the one standing a chance to sit. If the answer is no, the students remain sitting. Lots of fun, and the kids seem to love it and always ask for it. Be careful that they don't get too excited and knock over any chairs.