Colleen Fitzpatrick, better known as Vitamin C, used to be lead vocalist for a band called Eve's Plum, so named after the actress who played Jan Brady on a certain television show. She did presumably graduate from high school at some point.
OK, that was weak. This, however, is a song that got played at a lot of 1990's graduations, much like a song originally composed by Johann Pachelbel around 1680. Accompanied by the NYC All-City Chorus, the song doesn't just interpret "Canon In D" - it gives the song lyrics.
I know that I'm being a little flippant about the blatant lifting of "Canon In D" this week, but Colleen Fitzpatrick wrote some heartfelt and reflective lyrics. They spoke to a lot of people, and even though the music was already written - the message really transcended graduation, despite the title.
Here she is performing the song on Australian television. Note that a lot of audience members know the words.