Square Root Day is an unofficial day celebrated on days when both the day of the month and the month are the square root of the last two digits of the year. ( wiki Square Root Day )
For example, the last Square Root Day was 4th April, 2016 (4/4/16), and the next Square Root Day will be 5th May, 2025 (5/5/25) and then not again until 2036 !
So we have to gather at 10:55 am. ( amended from previous time of 5:00pm) at the square picnic tables at the Museum of the Riverina, and chat about all square things. ( not that the Museum is square, it's very interesting, and hopefully it will be open now the event is earlier ) [ Start Time on this listing is limited to 15 min intervals so I will be there then anyway ]
And you can bring your squares, set squares, builders square, square ruler or just be a square. 
And you can choose to wear something square or with squares on it.
Plenty of parking all around the carpark.
PS : even the Geocaching Logo has many squares ! And this events GC code also has a 5 and a V !!