Two that I thought the list might find interesting....
First Tim Bray gave an overview of mod_atom -- including the things that
were hard about building an apache module:
... But I can't find his slide URL.. Tim?
... but he does have a blog post talking about some of it:
<http://www.tbray.org/ongoing/When/200x/2007/09/17/How-mod-atom-works>
And Brian also gave a presentation on mod_wombat:
<http://kasparov.skife.org/wombat_ac_us_08.pdf>
Of course, I think everyone should look at the mod_wombat stuff, since
my personal intention is to import it for 2.4 to the core :-)
-Paul