Psi IM — Qt-based XMPP client
Psi is cross-platform powerful XMPP client designed for experienced users. There are builds available for MS Windows, GNU/Linux and macOS.
OpenEMR is an open source medical practice management application (EHR EMR PMS) featuring fully integrated electronic health records, scheduling, electronic billing, internationalization, free support, a vibrant community, and a whole lot more.
Cross platform GUI for Maxima
wxMaxima is a cross-platform graphical front-end for the computer algebra system Maxima based on wxWidgets. It provides nice display of mathematical output and easy access to Maxima functions through menus and dialogs.
3D game engine (more powerful redesign of the Cube engine) and FPS game
NetHack is a popular single player dungeon exploration game that runs on a wide variety of computer systems.
Aleph One is the open source continuation of Bungie's Marathon 2 FPS game engine. Aleph One plays Marathon, Marathon 2, Marathon Infinity, and 3rd-party content on a wide array of platforms, with (optional) OpenGL rendering, Internet play, Lua scripting, and more.
The OpenGL Extension Wrangler Library is a simple tool that helps C/C++ developers initialize extensions and write portable applications. GLEW currently supports a variety of operating systems, including Windows, Linux, Darwin, Irix, and Solaris.
for the latest release see either - https://github.com/OGRECave/ogre - https://bitbucket.org/sinbad/ogre/ An efficient, object-oriented hardware accelerated 3D engine. It abstracts the differences between APIs and platforms and allows scene-oriented coding through an easy to use object model. Adaptable to multiple scene types (indoor, outdoor, whatever)
A PDF Reader and Note-taker for OS X
Skim is a PDF reader and note-taker for OS X. It is designed to help you read and annotate scientific papers in PDF, but is also great for viewing any PDF file. Skim requires Mac OS X 10.6 or higher.
Real-time audio synthesis engine and music programming language
N.B. SuperCollider is now hosted at GitHub, and the most recent versions can be downloaded from there. http://supercollider.github.io A real time audio synthesis engine, and an object-oriented programming language specialised for music. SuperCollider was created in 1996 by James McCartney, now (since version 3) released as free software.
Midi Sheet Music is a free program that plays MIDI music files while highlighting the piano notes and sheet music notes. Works on Windows, Mac OS X, and Ubuntu Linux.
A project that has moved to GitHub
GLFW is an Open Source, multi-platform library for creating windows with OpenGL contexts and receiving input and events. It is easy to integrate into existing applications and does not lay claim to the main loop. GLFW has moved to GitHub: https://github.com/glfw
Powerful desktop publishing software
Scribus is an Open Source program that brings professional page layout to Linux, BSD UNIX, Solaris, OpenIndiana, GNU/Hurd, Mac OS X, OS/2 Warp 4, eComStation, and Windows desktops with a combination of press-ready output and new approaches to page design. Underneath a modern and user-friendly interface, Scribus supports professional publishing features, such as color separations, CMYK and spot colors, ICC color management, and versatile PDF creation.
The XonX project is used by developers of XFree86 for Darwin and Mac OS X to share and distribute code and information. All of the code developed is committed to the XFree86 Project's CVS server.
OpenSource OpenGL Multiplayer Multiplatform Battle Zone capture the Flag. 3D first person tank game. Project has moved to Github: https://github.com/BZFlag-Dev/bzflag
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.
An open source Mac OSX RSS reader with support for RSS/Atom feeds
Vienna is an open source Mac OSX RSS reader with support for RSS/Atom feeds, article storage and management via a SQLite database, written in Objective-C and Cocoa. Feeds can be accessed directly, or through a syncing service supporting the Open Reader API, like BazQux.com, FeedHQ.org, InoReader.com or TheOldReader.com. Development now happens on GitHub: https://github.com/ViennaRSS/vienna-rss
Meteorologist is a free weather program for OS X. It allows users total control over their weather viewing, including simultaneous interlaced weather reports from multiple weather servers, multiple weather locations, weather alerts and much more.
A simple paint program for Mac OS X
Paintbrush is a Cocoa-based paint program for Mac OS X, similar to Microsoft Paint and MacPaint.
Qwt is a graphics extension to the Qt GUI application framework. It provides a 2D plotting widget and more.
Free church worship presentation software
Open Source Worship Presentation Software. This project has moved to Launchpad: https://launchpad.net/openlp
Mac OS X frontend for OpenSSH's sftp/scp tools
A multi-protocol instant messaging app for Mac OS X
Adium is an Open Source, multi-protocol instant messaging application for Mac OS X. Adium supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Bonjour, Gadu-Gadu, Novell Groupwise, SIP/SIMPLE (Text), and Lotus Sametime. Additionally, it supports all of these applications at once so, even if you have multiple IM accounts, you don't have to log into each account separately.
Portable OS X FOSS applications
OS X FOSS portable applications are packaged so you can carry around on any portable device, USB thumb drive, iPod, portable hard drive, memory card, other portable device (or also on your internal hard disk), taking your preferences with you.
Free project scheduling and management tool
GanttProject is a project scheduling application written in Java and featuring Gantt chart, resource management, calendaring, import/export (MS Project, HTML, PDF, spreadsheets). Learn more on http://ganttproject.biz