HipCal

For a long time I have searched for a simple online calendar that had several important features:

• Online, accessible from anywhere, but protected by password
• Easy to use, with multiple views (day/week/month/year)
• Ability to have never-ending recurring events, and the ability to set them monthly or quarterly.
• Some sort of reminder system to send me emails when things are due/coming up.

After about 2 years of searching, I found it. Well, it was born, rather. HipCal does everything I listed above, does a little more, and does it well. I am now getting text messages on my cell phone AND email when events are due. My main goal was to use this for reminding myself to bill clients, and it seems that it will do this well. As a bonus, HipCal also includes a Memos section and a Task/To-Do list. Everything is designed well, and it appears to be written using Web 2.0 goodness. Did I mention it is free? I just hope it stays free and stays around a long time.