Conference Management
pretalx
Web-based event management, including running a Call for Papers, reviewing submissions, and scheduling talks. Exports and imports for various related tools. (Source Code).
osem
Event management tailored to free Software conferences. (Source Code).
OpenSlides
Presentation and assembly system for managing and projecting agenda, motions and elections of an assembly. (Demo, Source Code).
motion.tools (Antragsgrün)
Manage motions and amendments for (political) conventions. (Demo, Source Code).
indico
Feature-rich event management system, made @ CERN, the place where the Web was born. (Demo, Source Code).