Yet another great block to add to courses is the Glossary block. You can add terms to the glossary and set it to display random, or most recent, plus some other options. Basically, every time a student goes to the Moodle course they will see the glossary term or key concept. It's like setting them up to learn by osmosis.
Obviously ESL and language courses can benefit tremendously form this feature, but anyone that ha key concepts can apply. I like it because students can get fresh content every time the page loads and they can effortlessly learn vocabulary, jargon, and the like. They may of course, also go into the glossary and look up the other words, perhaps to study for a quiz.