Now that Google's own "Add to Calendar" function has disappeared from Gmail, is there Firefox add-on or Chrome extension that automatically creates a Google calendar from Gmail? Email is the most frequent source of notifications for new events, so it would save many people a lot of time if translating a Gmail message into a Google Calendar event.
shows that the ability is still there in gmail. Without plugins. Are you sure it hasn't just moved from where you expect to see it?
When I send an e-mail with the title of How would you like to catch lunch? and include a mail body that looks like this:
And then I receive a message and click on the "Create event" option on the "More" pull down, I get this in Google Calendar.
Bearing in mind that the time zones are differing by one hour between the two accounts. The sender timezone was considered, and adjusted for the receiver.
I think this will work for you: http://boomerangcalendar.com/
It still doesn't have everything, but it's better than the simple create event feature built into gmail.