Chris Z said:i would say Kubix, the dev is currently working on a review system for it, i believe and might be useful since you're doing tutorials, but i'd suggest getting a forum with a review addon..
blong4life said:Id reccomend ATutor, you can set up instructors, stuudents, so they can ask qyeutions:
Demo: http://opensourcecms.com/index.php?option=com_content&task=view&id=373
Website: http://www.atutor.ca/