If you actually want a password then why not use the month you were born, again totally unforgettable.

Use a date that is memorable but add in an abbreviation for what that day is (a combination of numbers and letters are the hardest passwords for other people to crack). So something like 0924wed (if you got married on Sept 24) or 0690grad (if you graduated in June of 1990) or 0510bday (if your birthday is May 10th).

There are lot of services which require you to change your password periodically and sometimes you are not allowed to use your previous 10 passwords. It is a safety measure but can be annoying. You can cheat the system by just using the sameword and keep increasing the number. e.g. password1, password2, and so on ; then come back to password1. You could correspond the current month as the number as well, whatever works for your memory. But never write it down.