It depends on how crazy you would like to go..
Personally, I use a Content Management System (Moodle) to assess students via interactive quizzes, message boards etc. You can also have students upload audio files for which you can leave personal feedback and grade.
Here is a sample online Navi course I am working on and using with my students this year.
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torahskills.org]
Warning: It is a lot of work. However, you don't have to do everything at once. I also use Quia.com if you just want to create simple quizzes and games for students. The students appreciate the immediate feedback of the interactive quizzes.
Tzvi Daum
[
torahskills.org]
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twitter.com]