A friend of mine rides the Big Iron. He takes more computers than I have ever used, bundles them together into big clusters, then lets others run their long, complicated processes on them. When many people can't get their computers to work, they go to me. When I can't get my computers to work, I go to him.
He had, until recently, used the KDE mail and calendar tools. I use Thunderbird for mail, and pop open a Google Calendar window when I need my calendar. I had tried Sunbird a while ago, but found it slow and buggy and not significantly better than a Google web app. He mentioned that he was trying Lightning, the calendar plug-in for T-bird. So, I did too.
And my calendar tried to alert me to every event on my schedule for the last six months.
If it's the week or more after an event, Lightning, you can just assume I'm not going.
I had to turn off alerts. And what is the utility of calendaring software without alerts?
I'll keep on it for a while, though.