I've been using Mozilla Calendar for calendaring lately, and while I'm not too crazy about it (it doesn't pop up reminders reliably), it seemed reasonable enough. I made the mistake of trying to upgrade to the latest version, and now I'm stuck without it due to this bug that's been around so long, that the latest version of Calendar has a special pop-up message describing the issue when it occurs. The problem for Linux users, it seems, is that the libical library used by some other programs, such as Ximian Evolution, is different from what Mozilla Calendar uses, and it won't be until the next version of libical that this will be resolved. Uninstalling Ximian Evolution completely and installing a fresh libical would probably fix it, but I'm not going to bother... *sigh*