(Add materials from kontact.kde.org)
In addition to organizing, viewing and editing your events, KOrganizer also provides alarm notification for the events. If you like, KOrganizer reminds you of upcoming events.
This happens by a simple popup window, by playing a sound file or starting a user-defined program and is configurable on an event-by-event basis.
You can also suspend alarms and run the alarm notification without running the complete KOrganizer application. This will place a small icon in the system tray of your KDE control panel.