Effective and easy to use free antivirus
Contao Open Source CMS (fka TYPOlight)
Text mode file and archive manager for Windows
Kurisu OS 3.0
Proofreading Software for 20+ Languages
The leading Open Source survey tool
Notepad++ project is moving to GitHub:
Feature complete address book written in PHP for your personal website
PXell - Online project management.
Open Source photo Library Software
The Swiss Army Knife of System Recovery
Free and open source webmail software
Create and edit SVG graphics directly in ownCloud. Based on svg-edit.
TuxWordSmith uses XDXF dictionaries to play in 88 languages