Since presentation slides are presented linearly usually, we wanted to change the way students can explore the content of our class. Therefore we designed a system with Slidestacks, which are a set of slides that issue one topic. These Slidestacks are tag-able, the system then creates a structure based on the tags, which consists out of Categories and Topics. Where Categories include a collection of Topics, and Topics are one or more Slidestacks.
Each of these Topics and Slidestacks is presented as FrameScrub like you probably know it from iPhoto albums.
For more details, please have a look at my Bachelor Thesis.