Drupal is an open-source content management platform for building web sites. It is maintained by a huge community of developers, and used on thousands of web sites, ranging from the newly launched Recovery.gov website, which supports and documents the American Recovery and Reinvestment Act put forth by the Obama administration, to Spin Magazine, Mother Jones, Slate, Virgin, Nokia, Oxfam, and more. Drupal itself provides core functionality (user accounts, permissions, basic content types), as well as a well-thought-out system of extensibility. Modules built and maintained by developers in the Drupal community tie into Drupal and add features, while Themes can be built to make the site match a designer's vision.
A Drupal Camp is a community-produced event where people with an interest in Drupal come together to learn about Drupal and share their knowledge of Drupal. In Seattle, we offer a mix of formal presentations, self-organized work sessions, and networking space at our camps, and often people from the Vancouver BC and Portland OR areas (and everywhere in between) come to our events. We have an external page listing different types of events we have held or might hold in the future.
The Seattle Drupal Users Group is an informal organization of people interested in Drupal in Seattle. We hold monthly meetings to discuss Drupal and share new things we've learned, usually in downtown Seattle, which anyone can attend. Before the meetings, and sometimes at other times, we have "co-working" time, where we meet and work on our own Drupal projects, in an atmosphere of sharing ideas. We have an IRC channel and a forum, where people post Drupal jobs, ask questions, and announce news of interest to the local Drupal community. And we also put on Drupal Camps.