[eukaryote]

I use a simple version of a TO-DO list. I have a email folder ACTION, and mails with a subject prefix of TODO are moved there with an auto-rule. My wife also adds reminders to the TODO list as required.

This works well for me; I have weekly timesheet and billing to do, and it keeps track of where I am in the workflow. An automated job on my server mails me the weekly tasks required in the subject, and I delete each mail as the task is complete. For example my weekly automated tasks are

   TODO: create invoice
   TODO: add invoice to finance spreadsheet
   TODO: complete timesheet
   TODO: save approved timesheet
   TODO: mail invoice and timesheet to customer
   TODO: confirm scheduled payment received
   TODO: perform weekly backup
   TODO: CAR1 check oil
   TODO: CAR1 tyre pressures
   TODO: CAR1 water jet reservoir
   TODO: CAR2 check oil
   TODO: CAR2 tyre pressures
   TODO: CAR2 water jet reservoir

This allows certain tasks to be performed when the weather is appropriate.