OpenSource community

MPlayer

HandBrake is an open-source, GPL-licensed, multiplatform, multithreaded DVD to MPEG-4 converter, available for MacOS X, Linux and Windows.

BZFlag is a free online multiplayer cross-platform open source 3D tank battle game. The name originates from "Battle Zone capture the Flag". It runs on Irix, Linux, *BSD, Windows, Mac OS X, and many other platforms. It's one of the most popular games ever on Silicon Graphics machines and continues to be developed and improved to this day. It's one of the most popular open source games ever.

Dr. DivX is an all-in-one video creation package that lets you create DivX video from any source right on your computer in just 3 easy steps. At this time, Dr. DivX is available in an English language version only.
Dr. DivX was designed to let anyone from the widest eyed newbie to the most grizzled expert create high-quality DivX video from any source in just 3 easy steps. Just choose your video, select your settings and click encode. Once encoded into DivX video, you can store entire video libraries on your hard drive without gobbling up precious storage space. Now you can post your video online, burn it to a CD or email it to your friends. And, with a DivX Certified DVD player, you can watch your DivX movies right on your living room TV.

"WinDirStat is a disk usage statistics viewer and cleanup tool for Microsoft Windows (all current variants)."

Adium is a free instant messaging application for Mac OS X that can connect to AIM, MSN, Jabber, Yahoo, and more.

GParted is the Gnome Partition Editor application. Before attempting to use it, here is some basic background information.