Review for Open Google Calendar by Firefox user 923844
Rated 5 out of 5 stars
awesomely simple. just using a browser tab to access the calendar in google. :-)
unfortunately, as of recent, a banner from google pops up saying "this browser version is no longer supported". the add-on still works for the moment, but who knows for how long.
To create your own collections, you must have a Mozilla Add-ons account.