T4LT - Interlude
Interlude.fm is a mashup video + branching scenario editor. And it's more than that as the scripting platform they call the Treehouse allows for loops and skips and a menu layer over the video. An app like this will require some planning and storyboarding, but the results can be really engaging.
A few notable videos to check out:
Khan Academy - Basic Fractions Demo: http://in.fm/v/AnprBM
Doona Instructions Interactive: http://in.fm/v/V1xQGA
Panera Interactive Training: http://in.fm/v/MYOprA
Healthcare Example: http://in.fm/v/V1wpGz