Set universal passwords for content (password based on day of the week).
RUPs allows you to set 7 passwords - one for each day of the week. You can then hide content using the shortcode [rups]content here[/rups]. Once your visitor supplies the appropriate password to the form, the content will be shown to them. Passwords are salted and hashed using sha512.
Your visitor must know the correct password for that day to view the hidden content.