No this is not the GAME of PingPong (we call it table tennis!) but an app that makes getting feedback from students simple and effective.
This app comes from the genus including Socrative and Geddit and has some of the features of Nearpod. Its selling point (well it is free!) is how quick and easy it is to get students feedback, ideas, sketch, or vote.
Students join the class with a simple class code (mine was a simple gport3, rather than the nuclear launch codes I have seen from some apps) and then you can run real-time questions anytime in a lesson from your iPad or iPhone, including multiple choice, true/false questions, plus a text response or best of all for me, a freehand drawing (such as the answer to a Maths problem). Teachers get the responses in real-time and in the first two cases a graph showing the class responses.
Another great feature is being able to use a whiteboard so if you are using Reflector to show your screen you can draw within the app and run a quiz.
Results can be exported to Evernote. You can also open documents, the drawback here is they need to come from Evernote.
Check it out here