What do you believe is the purpose of grades?
External sources (Grad Schools, Jobs, etc)
43%
Motivate students
14%
Evaluate students
43%
Total votes: 14

Here’s something cool you can do with Google Docs. I’ve created a couple of short self-diagnostic quizzes so that students can practice distinguishing between valid and invalid arguments.
Feel free to embed these in your own course webpages.