A online library project with a login module separating the librarian (admin) and the customers.
Sensible data are encrypted in a DB obviously.
Admin has a "management" page where he can manage borrowed and returning books from customers, add and delete, books and authors from the catalog.
She can also add or delete customers, so that those customers who are registered at the library can see in their profile section which books they have borrowed and those they have to return at a given date.
The customer, on top of consulting his profil page, can also browse the online catalog of books available.