Ironically, when you guys said "Mamma Mia" and "Spring Awakening" as plays, they originally plays. I'm not sure what the titles were, though. I just know that Spring Awakening was derived from some turn of the century play, and that both Mamma Mia and Carmelina (a flop musical from the seventies) were adapted from the same play.
"There are only two worthwhile things to leave behind when we depart this world of ours: children and art."
-Sunday In The Park With George