Here is a handy little report that gives you uncompleted tasks by organization.

It first gets the qualifying organizations by using a standard filter with "tasks -> status code is less than done" criterion. It then has a nested table which also uses a standard filter with relationship "pending tasks".

Download here.

Uncompress, run and enjoy.

I like this report, but I would like to run it by project rather than by organization. Anyway to easily customize it to pull by project rather than org?