Neutron is probably the most complicated piece of OpenStack because of the ability to integrate many networking plugins and because of the need to interact with security, instances, and users. Alok Kumar has put together a Theory of Everything in Neutron.
Need a consistent interface for provisioning and configuring a SQL or NoSQL database in a complex cloud environment? Consider Trove for your Database as a Service.
If you are using Ansible to manage your OpenStack cloud, you might be interested in a project to capture playbook logs to a database to make it easier to browse and troubleshoot.
If you use in-flight Wi-Fi, chances are you've used satellite broadband from ViaSat. OpenStack is an important part of their development environment.
Jigar Desai gets to introduce himself as VP of cloud and platforms at PayPal. Probably some Lando Calrissian comparisons get made. He recently talked about PayPal's use of OpenStack.
VMWare is all in for OpenStack; at least for OpenStack running VMWare.