Tactile Portraits also offers "whiteboard videos". This novel style of presentation shows hand-illustrations being drawn while narration provides detail and context to the visuals (usually in a playful and glib manner, as shown in this sample).
This promotional whiteboard video - Tactile Portraits' inaugural video - was 100% illustrated, animated, and narrated* by David Brennan.
*Well, I processed my narration a heck of a lot. I really don't sound like I've just sucked in a tank of helium!