As a WordPress shortcode,
[mcsf_events calendar="CALENDAR" key="API_KEY" class="OPTIONAL_CLASSES"]
where:
CALENDAR
is a Google Calendar resource, e.g.username@gmail.com
API_KEY
is a valid Google API browser key
See comments at the top of events.js for details on how to filter displayed events.
Yes, this is terse. Here, have a picture: