I'm one of the contributors to PhotoPub. I also have my own CVS branch, where I play with all sorts of fun things, before they get made sensible and included in the main tree.
If you'd like to live a bit more on the edge (typically) than the main branch, you can play with my version:
cvs -d :pserver:anonymous@urchin.earth.li:/srv/cvs login [password is "urchin"] cvs -d :pserver:anonymous@urchin.earth.li:/srv/cvs get -r nick photopub
I have also been know to release my own versions of PhotoPub. Typically this happens around the same time as a main branch release, but contains my tweaks/changes etc. You can see these releases here.
Before I had my own branch in CVS, I produced patches. For the really bored, they can be found here.
Nick Burch <code@gagravarr.org>