Dated reminders in sharepoint calendars

Expanding on Andy's answer (http://www.andrewconnell.com/blog/articles/CreatingCustomSharePointTimerJobs.aspx) if you just put code to send an email in the Execute method of the timer job this doesn't give you anything more than cron.

What you could do is to write code to iterate through the Calendar (actually an Event List) finding any events due soon and sending email to whomever is in the Assigned To field. This could then be called from the Timer Jobs Execute method or using a normal scheduled task. This will be easier to administer changes than cron and could be used for other types of tasks.

A link to get you started - Iterate through Items in a List

Another option would be to use Workflow to send out emails from the calendar

EDIT - Since SharePoint SP2 this no longer works as is as workflows can no longer start themselves (loop) - explanation and workaround

This CodeProject article shows how to develop a feature to send scheduled reminders

Yet another option would be to use one of the 3rd party tools that do this (disclaimer - I work for the first company)

• Pentalogic - SharePoint Reminder
• Bamboo - Alert Plus
• BoostSolutions - Alert Reminder Boost

Finally - whichever method you choose (custom code/workflow/3rd party) you will likely run into trouble with recurring events as SharePoint doesn't provide a way to get an 'expanded' list of all occurrences.

The best way to do this would be using a Timer Job - see Andrew Connell's blog here: http://www.andrewconnell.com/blog/articles/CreatingCustomSharePointTimerJobs.aspx