Appointment Slots away and then gave them back to .edu accounts last year? At the time there were no great free alternatives. Now, we still have Appointment Slots, but we also have Calendly.
Calendly is the perfect tool for scheduling time to meet with your colleagues, book parent readers for I love to Read Month, volunteers for a school event and even for scheduling parent teacher conferences.
The best thing about Calendly is that it dynamically interacts with your Google Calendar, so as you fill out your Google Calendar, Calendly adjusts the time slots available to the public. Give it a try!