Memo to Me - Online email & SMS reminder service.
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
Date Reminder - Date Reminder reminds you of recurring or nonrecurring events, like birthdays, bills to pay...
Gnome Clocks - Clock application designed for GNOME 3
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.
Simply Remind Me - Free email and text reminder service so you don't forget the important things in life!