Build It Green

http://builditgreen.org
Website redesign, membership and event management with CiviCRM 1.8 and Drupal 5.2
Civi integration included

Profiles for custom user registration and membership information.
Profile-based listings.
Custom smart group based listings.
CiviContribute,CiviEvent, and CiviMember to handle donations, event registration, and membership renewal.
Custom smarty templates for profile and payment pages.
A multi-step membership application built from civi profiles.
Registrations of multiple participants on a single CiviEvent signup form.
CiviMail using IMAP-to-Soap
Import of legacy membership data.
Synchronization of membership status with Drupal user role.
Customization of My Account page to show Civi Custom fields (using API).
Integrated membershihp zip code proximity search using Drupal's location search module api.
And a bunch more

This site really pushed Drupal and CiviCRM to their breaking points. Due to the complexity of Build It Green's membership structure, this turned out to be a less than ideal solution, and required way more custom coding than originally planned. The structure of their membership requires most memberships to be tied to Organization records. However, all user accounts are Individuals. This means is that if an Organization has a membership, all employees of that Organization also have membership access. And the primary contact for the Organization can renew and pay for the Organizations membership. This is not really the way the Civi membership model is intended to work, and it ends up breaking some of the default Civi business logic. For example, Indviduals pay for memberships of an Organization (not their own membership).

Performance has been terrible, and we're still looking for solutions. Although this is partially a bottleneck in Drupal's module system. Hosted at MediaTemple.