Our Yacht Club client has three workslips that members can reserve for up to 3 days. Using core taxonomy, content types, views, and the Events, Conditions, and Actions (ECA) module, we built a system to allow members to make reservations, and have the system prevent double-bookings.
Event Registrations
Send a roster of event attendees to staff
One of our clients is an art gallery that has a daily light show with limited seating. Reservations are free, but the show is popular enough that you need to reserve a month out.
Each day, they print a list of reservations for the staff to use when admitting guests.
Automatically show future and past events in a region
Another automation we did for Programming Librarian, a site for librarians to plan educational programs, involved events. They wanted to always feature 3 events on the home page, and the most important events were in the future. If their schedule is full, they wanted 2 future and 1 past event visible -- but they don't always have upcoming events, so there might be 0, 1 or 2 future events, and 3, 2, or 1 past events.
Aggregate fields in Drupal 8 views
Views module has long been the killer feature of Drupal, making it easy for a site builder or skilled administrator to essentially create complex SQL queries through a web interface, without knowing SQL.
NWETC
The Northwest Environmental Training Center (NWETC) is an organization that is committed to helping environmental protections improve their career opportunities. The organization focuses on two different offerings within the realm of environmental training.