This site has some really interesting features. With a nice visual integration with Google Maps, a robust display of parking lot locations can be accessed. Clients can visit parking lots and see if there are spots available. If so, they can rent a parking spot on line through the integrated e-commerce platform.
Parking spots can be reserved, placed on hold and made available for clients to join a waiting list. Registered tenants are billed automatically through PayPal on a monthly basis, and can cancel their spot reservation any time.
This website is a great example of a highly customized ubercart implementation with Drupal.