OpenClick is a free open source program that replaces the product iclickr in the classroom. Teachers can ask questions and students answer them with their phones. Live statistics shows how well your class is doing and if the lecture is effective. This is a web based application using the MEAN stack (Mongodb, Express, AngularJS, Nodejs) along with socket.io for real time communications. The best part is that it is completely free and only requires an Internet connection for students.