Alarmy - World's most annoying alarm app

Calendar Lock PEA - Calendar Lock PEA is an encrypted desktop calendar with a day, week and month view. The shown calendars are never stored unencrypted on your disk, but exist only in the RAM. Platform-independent, Open Source, no installation or registration required.

Galarm - Social alarm clock and reminders

Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...

Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.

UKs Kalender - This program helps you organizing your dates and tasks and reminds you of upcoming events.