remindme
RemindMe is a command line tool to allow you to set reminder messages for a date/time which will then be emailled to you.
Reminders are stored in ~/.remindme/jobs in a simple flat text format (so other scripts can easily create entries by appending to the file). RemindMe comes as two programs, one to create the entries and another that runs as a cron job to read the reminders and send the emails via SMTP
Requires Python.