Choose an avatar and type (text-to-speech) or record your voice. The app creates an animation. You can also customize the background with photos or drawing. You can share the animations using Facebook, Twitter, email, text message, or URL.
Limitations: Free as of 3/5/2014, but may become a paid app.
Students submit written assignments via a dedicated email address, and the instructor uses this app to annotate the submission, including text notes and drawing. The app exports the annotated submission as a PDF and sends it back to the student.