A fast cross-platform FTP client
FileZilla® is a cross-platform FTP, SFTP, and FTPS client with a vast list of features, which supports Windows, Mac OS X, Linux, and more. FileZilla's dynamic tools help you move files between your local machine and your Web site's server effortlessly. For example, Filezilla lets you compare your files with in-directory server files to manage file syncing. You can also tab browse between servers and transfer files to them simultaneously, as well as edit server files on the go. And Filezilla is available in 47 languages worldwide!
A free multi-track audio editor and recorder
Audacity is a free, easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems. The interface is translated into many languages. The version currently hosted here is 2.1.0 (March 2015). More recent versions than this are available from http://www.audacityteam.org/download/ . Audacity is free software, developed by a group of volunteers and distributed under the GNU General Public License (GPL). Programs like Audacity are also called open source software, because their source code is available for anyone to study or use. There are thousands of other free and open source programs, including the Firefox web browser, the LibreOffice or Apache OpenOffice office suites and entire Linux-based operating systems such as Ubuntu
Panorama photo stitcher
With Hugin you can assemble a mosaic of photographs into a complete immersive panorama, stitch any series of overlapping pictures and much more.
Free data backup software to synchronize files and folders
FreeFileSync is a free Open Source software that helps you synchronize files and synchronize folders for Windows, Linux and Mac OS X. It is designed to save your time setting up and running data backups while having nice visual feedback along the way. _______________________________________________________________ Support FFS with a donation: https://www.freefilesync.org/donate.php
A cross-platform GUI library
wxWidgets is a C++ library that lets developers create applications for Windows, Mac OS X, Linux and other platforms with a single code base. It has popular language bindings for Python, Perl, Ruby and many other languages, and unlike other cross-platform toolkits, wxWidgets gives applications a truly native look and feel because it uses the platform's native API rather than emulating the GUI. It's also extensive, free, open-source and mature.
A 3D simulator game where you can drive, fly, and sail
Rigs of Rods is a 3D simulator game where you can drive, fly and sail various vehicles using an accurate and unique soft-body physics engine. Since 2014, the development continued at https://github.com/RigsOfRods/rigs-of-rods UPDATE: 10/30/2016: removed opencandy installers, replaced with zip files.
WikidPad is a wiki-like notebook for storing your thoughts, ideas, todo lists, contacts, or anything else you can think of to write down.
Virtual Pipe Organ Software
GrandOrgue is a sample based pipe organ simulator. When connected to MIDI keyboards and an audio system, it can accurately simulate the sound of a real pipe organ. This application has builds for Linux, Windows and OS X.
A cross platform file and folder mass renamer, allows many different renaming operations in a GUI. Please note that development has moved to GitHub: https://github.com/metamorphose
Open Source Client/Server Network Backup System
Efficient Client-Server Backup system for Linux, macOS and Windows. A client for Windows, macOS and Linux lets you backup open files and complete partition images (Windows). Backups are stored to disks in a efficient way (deduplication) on either Windows or Linux servers.
Dr. DivX 2.0; officially the unofficial DivX encoding tool to create DivX Media Format files for playback on DivX hardware and software players.
WASTE is a mesh-based workgroup tool that allows for encrypted, private communication between distant parties on the internet, independant of local network organization.