Google has made it even easier to add events to your Calendar directly from your Gmail. You can now see that dates and times are lightly underlined within an email. Please note that the email won’t be underlined if you send it to yourself from your own account.
Here is a screenshot to show you this handy feature:
When you click on the underline, you’ll be able to preview the schedule and make any changes and simply add the item to your Calendar. The scheduled event will even include a nice link back to the original email.
This feature is currently only available in (US) English, but Google is working on adding it to other languages.