Indico is a general-purpose event management web-based solution. It includes a full-blown conference organization workflow as well as tools for meeting management and room booking. It provides as well integration with video-conferencing solutions.
A list of features can be found here. There is also a video!
Indico is free software, licensed under terms of the MIT License. It is currently in production at CERN, as well as in many other scientific institutions around the world.
Information on how to get the latest release can be found at the project web site. If you are interested in contributing to Indico, you can consult the project documentation.
The project web site is https://getindico.io and the developers can be reached via IRC (#indico on Freenode).
Indico was created at CERN, originally as part of the European Union's InDiCo Project.
In applying the MIT license, CERN does not waive the privileges and immunities granted to it by virtue of its status as an Intergovernmental Organization or submit itself to any jurisdiction.