Nullboard - Minimalist locally-stored kanban board / task list manager.
Traq - Traq is a PHP powered project manager and issue tracker featuring multiple projects, milestones...
Huboard - HuBoard is built from the ground up using the GitHub public API.
Bugify - Bugify is a simple PHP issue tracker, designed to offer powerful bug tracking capabilities in an easy to use system.
Zube - Project management for developers.
jtrac - JTrac is an open source and highly customizable issue-tracking web-application written in Java.