You can be warned of upcoming events if you set an alarm for that event. Alarms are set simply by clicking on/off radio boxes in the Set Alarm section of any Event form, and adjusting hours and minutes in alarm time. If you want to repeat alarm every n minutes, you adjust snooze every n minutes (snoozing does not continue in the day after). When alarm occurs, you can set various Alarm Actions to happen (like playing sounds, displaying message, starting other programs etc). No alarm can happen if you switch them off in tray icon menu or Config.