Read a book, magazine or blog post of personal (and school appropriate) interest.
Work on an assignment for another class.
Play a pre-approved game that builds skills related to the class. (If you find a game that you feel contributes to your learning, tell me about it and why you think it should go on the approved list.)
Have a serious discussion with a classmate about a topic in the course using an approved discussion tool.
Listen to an educational podcast or view an educational video. TED talks and Khan Academy videos are always OK. (Remember to use your headphones.)
Organize your life by reviewing/updating your calendar, to-do list, or address book.
Write in your personal journal.