You forget, lose or your Super Admin (or other user account) won’t allow you access to your system.
Reset password using PHPMyAdmin
If you have access to PHPMyAdmin then you can edit the account that you want to reset the password for and as long as you follow the screencast shown below you can enter your password in plain text and have it encrypted for you as it is saved to the database.
Just make sure that you choose the same encryption method that your site is currently using.
(Sorry that the file isn’t uploaded to the Wiki but apparently it is too large to upload. Admins it might be nice if the Upload File page had a message on there telling people just how big a file can be uploaded 😉 )
Alternatively if you have a Forgotten Password section on your site somewhere it might be best to try that out first.
Hope that helps someone though.