Synkron is a simple Qt application that allows you to sync folders, for example a flash disk with a folder on your hard disk.
Smultron is a text editor written in Cocoa for Mac OS X Leopard 10.5 which is designed to be both easy to use and powerful.
LinPHA is an easy to use, multilingual, flexible photo/image archive/album/gallery written in PHP. It uses a SQL database to store information about your pictures. It comes with a HTML based installer, so you don't need experience in setting up SQL
GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching geometry, algebra, statistics, and calculus. Download the free software at http://www.geogebra.org. Find the source code at http://www.geogebra.org/trac
An eMule client that is based on the original one, but with a new credit system.