Rather than have you keep weekly journals each week throughout the semester (as I did last year), I'll have each of you e-mail your summaries of a week's lectures and readings only three times over the course of the semester. This way, the listserver won't overwhelm us and yet the quiz journals can motivate you to keep up with the class so you don't get swamped right before the tests.
The idea here is you need to devote a solid three hours a week to reading the lectures in addition to the outside textbook reading that you would normally expect to do in a class. If you are keeping up with the class, you'll have little trouble coping with the pop quizzes. If you haven't, well, the pop quizzes will be pretty inconvenient!
At three random points in the semester, I'll e-mail you your pop quiz and have you answer it online in an e-mail essay or outline for the benefit of your peers. In each case, you'll have two days to respond (which is long enough for you to do a good job but short enough to be overwhelming if you haven't been keeping up with the lectures and readings). It is important to keep an eye on your e-mail! The idea here is to have you help your colleagues by summarizing and reinforcing the high points of that week's lecture and readings (and yourself by making sure you're staying up with things). These random pop quizzes will be graded for overall content, sophistication, and helpfulness, but will not be graded for writing mechanics due to their informal nature.
Basically, you are trying to convince me that, in fact, you did read the lectures and textbook and thought about what you learned. In about two screens, summarize the five or six major concepts you got out of the lectures from the designated week and five or six major ideas from the textbook assignment for that week.
Another thing you are trying to do is help your colleagues get more out of the week in class by drawing their attention to what you think the main concepts or processes were. I may use a few of your pop quiz ideas to create test questions, too, so "think like an instructor" and imagine what sorts of things you might test on if you wound up teaching this class someday!