WPMU DEV - WPMU offers WordPress Plugins, WordPress Themes, WordPress Multisite and BuddyPress Plugins and Themes.
AsciiMath - Easy-to-write markup language and JavaScript display engine for mathematics
MAMP - MAMP is the abbreviation for Macintosh, Apache, MySQL, and PHP. It is a reliable application with its four components that allows you to access the local PHP server as well as the database server (SQL).
WordPress themes - Find the perfect theme for your WordPress website. Choose from thousands of stunning designs with a wide variety of features and customization options.
Firefox Developer Edition - Built for those who build the Web. The only browser made for developers.
.NET - .NET is a free, cross-platform, open source developer platform for building many different types of applications.