Nadia Borissova, Assistant Director of GILEE, in the Andrew Young School of Policy Studies, sent along an app that may be of great use to you. Zamurai Mobile Whiteboard is a freemium iPad app, allowing basic functions for free with more extensive features for $6.99.
It’s major use is as an infinitely sized whiteboard which can be captured for later use, turning a simple presentation into an engaging discussion. Simply plug your iPad into your classroom’s display, and start working with your class on developing your ideas collaboratively.
This app goes beyond other drawing apps like Paper, by utilizing a library of flow chart images and various other tools that help with rapid content creation, and would go well with apps like Explain Everything, which allow full collaborative annotation of many different file types.