Teachers and students can create fake profiles and then create interactions between other related fake profiles. Click here for a listing of the ones created so far. For example: Ernest Rutherford, Joseph Stalin, Henry Ford.
How about create an interactive jigsaw diagram. Here are some examples: Fractions, Water Cycle, Industrial Revolution.
Create a timeline. You can create it correctly or mix it up and have students re arrange it. Here are some examples: Harper Lee, Romeo & Juliet, Galileo.
Other useful applets include a plagiarism checker, a timer, and other organizational tools. Note that by becoming a member you can get rid of the ads.