At the 2009 Melbourne International Comedy Festival, the Axis of Awesome played their Four Chords Song, and it became really popular, with that video having over 30 million views, and their 2011 official music video (with a slightly different set of songs) a tick under 20 million.
If you read the comments on the Pachelbel Rant video, you get things like this:
Was disappointed when the group "AxesofAwesome" completely ripped it off with "Four Chords".
I just realized that Axis of Awesome completely stole the concept of this video.
And OK, maybe those are the only two comments accusing the Axis of Awesome of plagiarising the concept. But I want to respond to them here anyway, because yesterday I discovered this video by Benny Davis (keyboardist for the Axis of Awesome) singing an early version of the Four Chords Song in November 2006.
So there we go, independent (re-?)discoveries of a piece of musical comedy.