GanttProject is a cross-platform desktop tool for project scheduling and management. It runs on Windows, Linux and MacOSX, it is free and its code is opensource.
Gephi is an interactive visualization and exploration platform for all kinds of networks and complex systems, dynamic and hierarchical graphs. Runs on Windows, Linux and Mac OS X. Gephi is open-source and free.
This is a suite of macros to perform basic statistical analysis within OpenOffice. These macros give OpenOffice Calc the functionality which Analysis ToolPak gives Microsoft Excel, and many of these routines are unavailable in Excel.
CommentPress is an open source theme for the WordPress blogging engine that allows readers to comment paragraph by paragraph in the margins of a text. Annotate, gloss, workshop, debate: with CommentPress you can do all of these things on a finer-grained level, turning a document into a conversation. It can be applied to a fixed document (paper/essay/book etc.) or to a running blog.
A complete Web Authoring System for Linux desktop users as well as Microsoft Windows and Macintosh users to rival programs like FrontPage and Dreamweaver.
BitNami bundle many popular Open Source software packages into a 1-click setup file. Theoretically, all a user has to do it download the package of their choice and copy it on to their system or web host.