Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
GetBadges - GetBadges is a gamification platform which allows developers to play and compete while using software development tools.
Anchor CMS - Free and lightweight blogging system
Goals & Challenges by Fini - A social way to gamify goals and habits with challenges
Textpattern - Textpattern is an elegant content management system that is free, open source software.
HabitScript - Gamify your coding time