ReactOS® is a free, modern operating system based on the design of Windows® XP/2003. Written completely from scratch, it aims to follow the Windows-NT® architecture designed by Microsoft from the hardware level right through to the application level. This is not a Linux based system, and shares none of the unix architecture.

Synfig Studio is a free and opensource animation software available for Windows, Linux and OSX.

Web conferencing that just works. Dimdim provides easy, open, affordable collaboration. Use for online meetings, eLearning, desktop sharing, training, distance education, unified collaboration, webinar, free web meetings and more.

"The Guide is an application that allows you create documents ("guides") which inherently have a tree (which you can modify as you please) and text associated with each node of the tree. The text itself is of the rich-text variety, and the editor allows you to modify the style and formatting of the text (fonts, bold, italics etc).For the initiated, the Guide is a two-pane extrinsic outliner. This concept is similar to mindmapping in some ways."

Songbird is an open-source customizable music player that's under active development.

"Zenphoto is a CMS for selfhosted, gallery focused websites. Our focus lies on being easy to use and having all the features there when you need them (but out of the way if you do not)."

http://www.codeproject.com/

open source code

jEdit is a mature programmer's text editor with hundreds (counting the time developing plugins) of person-years of development behind it. To download, install, and set up jEdit as quickly and painlessly as possible, go to the Quick Start page.

The following apps and resources are categorized by SIP, H.323, IAX, and RTP protocols and include clients, libraries, gatekeepers, and any other open source resource available for those specific protocols plus PBX and IVR platforms

Some neat sites with more info about FreeDOS, and DOS in general.

a library for linux+windows for graphics