The only Moxy song I know is their version of
Green Eggs and Ham, which isn't a cappella, but is very clever.
And for Da Vinci's Notebook, I've been thinking about picking up some of their CDs, but just haven't gotten around to it. Here's the beginning excerpt (mp3) of their song
Title Of The Song, which is a brilliant deconstruction of every boy band ballad you have ever heard.