inurl:calendar.google.com/calendar/embed?src=
This will bring up publicly available Google Calendars. For example, using
this dork you can find:
- https://calendar.google.com/calendar/embed?src=safekprocess@gmail.com
- https://calendar.google.com/calendar/embed?src=chris.hm.chan@gmail.com
- https://calendar.google.com/calendar/embed?src=kchan9@gmail.com