Time tracking application. We developed it initially for our own team but later sold it to few existing clients.
This application allows tracking time locally on miscellaneous tasks and then log it to external systems, apps and services. When you log your time into external service you can pick existing task there or create a new one on the fly and log your time.
These are just a few drivers we developed:
Also GetMyHours Django application provides detailed monthly calendar reports about your logged hours from registered external services.