EQ Checkout is a web application for inventory management. I designed it with Universities in mind, but it can work for any organization. There are a lot of university departments (and other organizations) that have equipment that they checkout to their users. EQ Checkout allows their users to make reservations online and helps administrators manage the equipment.
The application is a multi-tenant application. When a new organization signs up they create a subdomain (something.eqcheckout.com) and that becomes the URL that is used to make reservations, checkout equipment, and manage inventory and users. Each organization gets their own database and preferences.
I actually built a custom MVC framework for this application.
You can learn more about EQ Checkout here.