Which plugins are really being used?

I just started a new position and inherited a page that is just crazy. Hundreds of pages and/or posts, and a BUNCH of plug-ins installed that I am sure are either never used or only used on a couple of pages.

I was just wondering if anybody knew of a simple way to figure out what plugins are actively being used and where? Other than just going through each page and documenting which plugins they use.

Thanks!