International Day of Human Space Flight
https://www.un.org/en/observances/human-spaceflight-day
https://www.un.org/en/observances/human-spaceflight-day
https://www.nationaltrust.org.au/ahf/
https://www.un.org/en/observances/creativity-and-innovation-day
https://www.unesco.org/en/days/world-book-and-copyright
https://www.volunteeringaustralia.org/tag/national-volunteer-week/#/
https://www.reconciliation.org.au/our-work/national-reconciliation-week/
World Wide Knit in Public Day is the largest Knitter run event in the world. It started in 2005 and is now celebrated in 57 different countries (2016).
https://www.naidoc.org.au/
https://www.restartaheart.net/
https://nanowrimo.org/