I am not the biggest fan of students making
powerpoints, because I see so much copy and pasting and not so much reflecting. Still, I see so many beauutiful powerpoints done. Here is a way to retain and share those powerpoints. Authorstream retains animations and recorded audio.
Class idea: Have your students post ppts done for class presentations on slideshare and collect them in a wiki or blog for review. Students may listen more intently to their fellow students if they are accountable for content. This would give teacher a way to review what was done in class and create an assesment for other students, and students a mode of review.