Tenable Nessus is a world-leader in active vulnerability scanners. It features high-speed discovery, configuration auditing, asset profiling, sensitive data discovery, and vulnerability analysis of your security posture. Nessus scanners may be distributed throughout an entire enterprise, inside DMZs, and across physically separate networks. It is free of charge for personal use in a non-enterprise environment.
Bastille Unix (formerly Bastille Linux) aims to be the most comprehensive, flexible, and educational Security Hardening Program for Red Hat (Fedora Core, Enterprise Linux, and original Red Hat), SuSE, Gentoo, Mandrake, and Debian Linux, as well as HP-UX and Mac OS X. Virtually every task it performs is optional, providing immense flexibility. It educates the installing admin regarding the topic at hand before asking any question. The interactive nature allows the program to be more thorough when securing, while the educational component produces an admin who is less likely to compromise the increased security.
Seafile is a file synchronization and collaboration platform. It comes with Dropbox-like file syncing, but is designed to be better suited to teamwork. You can build a file syncing and collaboration service for your team on your servers. It can also be used to build your own Dropbox for personal use.
omnisode generates a Ruby program to use long Taylor series to solve systems of ordinary differential equations. It generates code to solve the equations in either Maple or Maxima. Using the Taylor series, estimates are made of the location and order of poles. It has been greatly re-worked the last few years, and tested quite a bit recently. Support may be extended to other languages in the future.
Monkey HTTP Daemon is a very fast and lightweight Web server for Linux. It uses a hybrid networking model based on asynchronous calls (event-driven) and fixed threads, which makes it scalable and capable of attending thousands of clients per second. It provides a powerful API for C and is ideal for embedded devices, thanks to its small core and plugin architecture.
Catdoc is a MS Word file decoding tool that doesn't attempt to analyze file formatting (it just extracts readable text), but is able to handle all versions of Word and convert character encodings. A Tcl/Tk graphical viewer is also included. It can also read RTF files and convert Excel and PowerPoint files.
Window Switch is a tool that allows you to move applications between networked computers. The windows appear where you need them, as they were. You no longer need to save and send documents to move them around; simply move the view of the application to the machine where you need it.