I've been trying on and off to figure out how to obtain a list of all
the TODOs that I've marked completed (DONE) during the last week (or
whatever time period, but typically I want the last 7 days). There's
undoubtedly some very simple way to obtain this that I just can't locate
for whatever reason.

I'm giving up and asking for help, can someone let me know how this is
done?  :)

FWIW, I've got things setup so that when I mark a TODO as DONE, CLOSED:
<date> gets added to the entry.

Thanks,
Chris.