It's just barely working and quite slow, but here's an initial tentative on a package to get the agenda in Org mode to show up in GNOME's calendar:
https://github.com/llvilanova/org-gnome-calendar Lluis -- "And it's much the same thing with knowledge, for whenever you learn something new, the whole world becomes that much richer." -- The Princess of Pure Reason, as told by Norton Juster in The Phantom Tollbooth