Google calendar invites contain attachments in standard formats you can use in Thunderbird or almost anything else.
Facebook events can do the same, but it does require you to have a Facebook account which is over the ethical line for me as I do not accept their terms of service. I always let community event organizers know this, and explain how to export events into a standard calendar format that can be emailed.
Facebook events can do the same, but it does require you to have a Facebook account which is over the ethical line for me as I do not accept their terms of service. I always let community event organizers know this, and explain how to export events into a standard calendar format that can be emailed.