Harry Potter the Musical?!

Basically; the best damn things your eyes have ever seen.
And YES I did purposely quote Avril Lavigne right there.
From their Youtube page one can find out that this was a performance done in early 2009 that a bunch of college/post-grad people did, performed for three days (5 shows) and are never doing again...BUT they did record it for all of the world to watch on Youtube :D
Below is the video for the first part of Act 1. If you click here you can go to the playlist page, and then watch them straight through.

Absolutely hilarious: you will be laughing the whole way through.
It's not just one book, more so a mix of all seven(: