Squeak, Seaside, Pier, and Smalltalk

Here is one interesting software development environment, especially for web applications. Squeak is an open source implementation of Smalltalk. Seaside is a Web Framework for developing web applications in Squeak. Pier is a CMS built on Seaside. DabbleDB is also built on Seaside -- an incredibly impressive web app. So far, I've installed it on my Mac iFive (OS X 10.4.10).