I’m a huge fan of thatquiz.org for many things, but especially math. In less than a minute I can create a quiz for review or practice. Students complete the quiz on the computer and get immediate feedback. It saves me time on grading and keeps a nice gradebook of all the quizzes. I also learned recently that you can print out quizzes you create if your students don’t have access to computers. This saves time with formatting and leaves the option open for computer testing. It isn’t a full-fledged learning management system, but it can certainly make your life a lot easier.
Here is a quick tutorial on how to use it. The site also gives some excellent directions.