Google Calendar - Repeating an event on the last <weekday> of the month

I regularly attend RORO - The Ruby on Rails Oceania meetups.
They currently occur on the last Thursday of every month and so naturally I put the event in my calendar. I added the usual details and then selected the "repeat" option and set it to repeat monthly by the day of the week.

This worked well for a while, until one day when I rocked up and it wasn't on.
A later realised that in that particular month there were 5 Thursdays instead of 4 and my calendar event was actually set to repeat "Monthly on the fourth Thursday".
It turns out that the interface Google provide to set recurring events does not allow you to change this.. or at least not intuitively.

After some searching around I found a few solutions:


Use English!

The simplest way is to just write out the event in plain English. For example:

RORO at Inspire9, Richmond on the last Thursday of every month

This will create an event called "RORO at Inspire9, Richmond", with the location field set to "Inspire9, Richmond" and the repetition set to "Monthly on the last Thursday".


Start repeating from an appropriate month

Another fairly easy way is to find a month that actually has 5 Thursdays and make the event start from there. This will set the recurrence to repeat "Monthly on the last Thursday", instead of "Monthly on the fourth Thursday".


Hack the ICS

This solution is probably the hardest, but because the iCalendar format does support this, you could write the code manually. To do this you would have to export the calendar to a file, hack it and import it back.
While it's nice to know this, seems like more effort that just typing what you want in English!


A better solution

.. would be if Google provided an additional option in the little "repeat" popup to allow this!

Or maybe the RORO organiser should maintain there own calendar feed that we could all subscribe to. This would also mean that if a particular meetup was moved or cancelled, all the subscribers calendars would automatically be updated!