We just finished reading "No Talking" which is such a funny book about a fifth grade class who just has trouble not talking all the time. They decide to have a competition, boys against girls, to see who can actually go without talking for two whole days. The ending is really shocking with a twist!
We tried this ourselves for two hours one afternoon at school and it was too funny! Watching everyone communicate without words was very interesting and some had to be pretty creative to get their points across without saying a word!