is there a good reminder pop-up utility?

[frankdn]

Can someone please recommend a calendar utility of the sort that generates pop-ups and alarm sounds when a planned-for event arrives? Thunderbird and Evolution both offer the features I need but I don't always have these programs running. I'm looking for something that starts automagically and runs as a daemon, but will still pop a dialog on my desktop when the time comes.

Thanks!

[ajgreeny]

The only one I know of, other than using gnome-schedule to pop up something is kalarm. OK, it's a kde app, but I imagine it works on gnome without problems, other than bringing all sorts of kde libs with it when you use it. There is also xcal, which I have just looked at and seems simple enough, but I know little about it, so can't comment any more.