So, I'm sitting here watching Max's Fedora presentation. About 5 minutes in... the screensaver kicks in on the top of the slides. gnome-screensaver should have a d-bus (or whatever) interface that allows people to temporarily disable it. (It may already have this, so see the next point....) OpenOffice.org, MagicPoint, totem, *whatever*... should use it if/when it exists.
Filing here instead of upstream as, even if the feature is an upstream issue, we need some way to track all the Fedora stuff that needs to hook into this.
Here's how we do it in Totem (updated to support 2.14 and 2.15 APIs): http://cvs.gnome.org/viewcvs/totem/src/totem-scrsaver.c?view=markup For apps that don't want to DBUS dependency you can do "gnome-screensaver-command --poke" once every few seconds or something. Hopefully, we can make this an org.freedesktop.ScreenSaver interface at some point which may help convince upstream packages to use it.