A calendar and contact server written in Python. selfhosted Supports HTTP, CalDAV, and CardDAV. Local and remote access. Compatible with anything that supports those protocols. exocortex switchboard Uses Git as its back-end by default, supports others but they're less tested. Lightweight, few dependencies. Events, todos, journaling. Minimal configuration to be up and running. Throw it behind a reverse proxy and it'll use the existing .htpasswd file as its native authentication system. Website isn't as up to date as the github repo is.