Gwibber - Microblogging client for GNOME

Gwibber is a microblogging client for the GNOME desktop environment. brings the most popular social networking services like Facebook, Twitter, etc into a single window and gives ability to control communication through one single application. It only runs on Linux and is written in Python using PyGTK. It ships with Ubuntu 10.04 and above. Gwibber supports multiple social networking sites in a combined social stream with URL shortening, saved searches, and a multicolumn UI.

Kgeography

Open source educational software

KGeography is a Free and open source educational software game that tests students geographical knowledge. Browse the maps clicking in a map division to see its name. Every nation's flag and capital will be shown as well. Besides for educational purposes, KGeography can be used for evaluating ones knowledge.

Marble

Open Source Geography Tool

Marble is a virtual globe that allows the user to choose among the Earth, the Moon, Venus, Mars and other planets. It is free software under the terms of the GNU LGPL, developed by KDE for use on personal computers and smart phones running a Qt4-compatible operating system. Marble is intended to be very flexible; beyond its cross-platform design, the core components can easily be integrated into other programs.

Openmeetings- open source web conferencing software

Openmeetings is open source web conferencing software. It uses red5, an open source implementation of Adobe's Flash Media Server, to support its real-time collaboration. In Openmeetings one can record their business communications or any other of same purpose.