Commoncraft makes videos using stick figures and cut-out paper that work to explain modern technologies in a simple, digestible form. Their use of the phrase "in Plain English" is a tad disingenuous, as their entire premise rests on the combination of their simple, diagrammatic visuals with the verbal explanation.
A minor quibble (and arguably their success is in communicating the big idea of a thing, which "in Plain English", while imprecise, does). They're quite good at what they do.
Here's their newest, a take on Twitter. It's not how I use Twitter currently*, but it's a pretty good explanation of why someone unfamiliar with Twitter might find value in it--and it's in the direction of how I see Twitter's value to some underserved populations, e.g. seniors and parents of preschoolers.
Some other of their videos include RSS in Plain English and Social Networks in Plain English.
*As a virtual space to crack wise.