BBC
A BBC article (click here) describes thumb twiddling as an ancient art and that it is a subject having many nuances and a depth not seen upon initial contemplation.
Wikipedia
Wikipedia has a perfectly dull article about thumb twiddling (click here). They say thumb twiddling is often cited as an example of a useless, time-wasting activity, an activity that yield no useful results.
Uncyclopedia
Uncyclopedia has an article about thumb twiddling (click here), which they say is an ancient martial art known as “thumb fu.”
Uncyclopedia shows a statue in honor of thumb twiddlers: