Yes - it's very simple:

contacts.txt - in order of surname, firstname

Surname, FirstName, Primary telephone number with code, Email address so:

   Joe, Bloggs, 02033345545, joe@bloggs.com

I only keep a single number for people, but you could extend it to two numbers if you want.

cal.txt - latest dates at top of file:

   2012/02/02 16:00+ What to do         # time specific event
   2012/03/03 --:--  Someone's birthday # all day event

When something is done, the line is deleted. If something is not done on the date, it is just left as "overdue" at the top.

I do something very similar for my calendar, but it's kept in markdown and instead of deleting the done items I move them under a heading for the date completed(along with any notes about the item). While I'm not required to submit a timesheet for my employment, I find it nice to have a log of my actions.

The contacts file sounds interesting, I'll give that a try.

Thanks for the information. Do you enter birthdays every year? Or just use sed or something to update the year? If you delete everything after the date, I guess you never need to refer to old appointments?

If it's a birthday, I actually manually add the birthday's next occurence to the appropriate point in the list. It helps keep the dates in mind as well!

So I guess you don't have Gmail's recipient autocompletion, or you do? This is the killer feature of Gmail for me, with its keyboard shorcuts and search.

I don't need to search. My inbox (my only folder) is 4 items at the moment. I rarely initiate an email conversation but whe I do it's simply select the addres from the text file and paste with the right mouse button.

Mutt has an autocomplete function but TBH I can't be bothered to set it up.