sleek is a todo.txt manager, free and open-source (FOSS)
Simple Online Planning
Freeplane add-on for task management and memo taking
The Freeplane add-on that syncs a GTD mind map with a todo.txt file
WeekToDo is a Free and Open Source Minimalist Weekly Planner and To Do
a free mind mapping tool, to especially assist decision making
Open source project management
Free flexible open source todo manager featuring hierarchical tasks
Generate Work Breakdown Structures (WBS) in Excel.
German Template for Bugzilla
Collabtive is web based project management software. Simple and easy.
Daily Task Management Software with Report Generation
PHP & MySQL/SQLite -based Project Management System
A free,beautiful time management app based on AIR.
Adam - information management platform
Open Source, tasks, bug tracking, agile scrum, timesheet, wiki
Personal organizer focused on usability and user productivity
SCRUM task board
A simple issue tracker system.