You forgot the fact that riding one makes you look like a total geek, and not in a good way. Al Yankovic's song "White and Nerdy" captures the image perfectly: http://www.youtube.com/watch?v=N9qYF9DZPdw
Yes. The thing was quickly adapted as a set-piece to communicate a certain flavor of nerdery and laziness in comedies. In addition to the music video you mention, there is also "Paul Blart Mall Cop" and GOB from "Arrested Development"