To Really Learn, Quit Studying and Take a Test. Research shows that you'll be able to recall 50% more information after a week if you're tested on the material as opposed to simply studying or doing concept mapping (another educational fad in vogue right now).
The study, "Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping" was recently published by Jeffrey Karpicke of Purdue University and graduate student Janell Blunt in the journal Science. Looks pretty compelling. I can't imagine, however, that my students would appreciate tests every week to help them learn the material.