GNU General Public License

K-Meleon is an extremely fast, customizable, lightweight web browser based on the Gecko layout engine developed by Mozilla which is also used by Firefox. K-Meleon is free, open source software released under the GNU General Public License and is designed specifically for Microsoft Windows (Win32) operating systems.

Redmine is a flexible project management web application. Written using Ruby on Rails framework, it is cross-platform and cross-database.
Redmine is open source and released under the terms of the GNU General Public License v2 (GPL).

The goal of Gnumeric is to be the best possible spreadsheet. We are not attempting to clone existing applications. However, Gnumeric can read files saved with other spreadsheets and we offer a customizable feel that attempts to minimize the costs of transition.

Gregarius is a web-based RSS/RDF/ATOM feed aggregator, designed to run on your web server, allowing you to access your news sources from wherever you want.

give your phone a break with this foursquare app for mac

Soundflower is a MacOS system extension that allows applications to pass audio to other applications. Soundflower is easy to use, it simply presents itself as an audio device, allowing any audio application to send and receive audio with no other support needed.

GNUnet is a framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services. A first service implemented on top of the networking layer allows anonymous censorship-resistant file-sharing. Anonymity is provided by making messages originating from a peer indistinguishable from messages that the peer is routing. All peers act as routers and use link-encrypted connections with stable bandwidth utilization to communicate with each other. GNUnet uses a simple, excess-based economic model to allocate resources.

Wave Alpha is a robot written in Python for the Google Wave platform. It empowers the user with the ability to query Wolfram Alpha's Computational Knowledge Search Engine right from a "wavelet" and retrieve the results right into the "blip".

MediaWiki is the best known Wiki engine. it is used for Wikipedia and many other projects inside and outside of the Wikimedia Foundation. Over time MediaWiki has grown in functionality and at the same time it became hard to use. This has been recognised and the Usability Initiative is developing much needed improvements to make MediaWiki more usable. Google Wave is a brave new attempt to bring new functionality to well established categories of applications like e-mail, text messaging, wiki and it does it by integrating the functionalities of all of them in a compelling new technology framework.