A conference schedule optimizer using mixed integer linear programming. This is used to generate the schedule for Electromagnetic Field events.
This uses OR-Tools, which should be automatically installed from pypy.
The concept and code for the original CBC-based version of this library is from David MacIver.
For more information on this approach, see David's talk Easy solutions to hard problems from PyCon UK 2016.
A similar library with a slightly different approach is conference-scheduler.