it's been a while since I last used Ubuntu and it looks like that Ubuntu changed a lot. Some fast questions would be is current default (Ubuntu 11.10) panel still gnome-panel or is it unity-panel or so? I know that it is possible to integrate into messaging panel, although my program is not oriented towards messaging (imo neither is ubuntu one), it's a google task synchronizer. What is the way to add my program to clock panel? A subquestion (a little abstract, but don't know how to address) would be, how is the calendar applet made and what are the requirements to make such?
SnapOverflow
Very good question. As I understand it, libido is responsible for the non-menuitem items in the indicator menus. I mean the calendar, media controls, etc. If I understand correctly, you should be able to add menu items as usual, like the "Time & Date Settings..." item.