The Australian cuisine is a melting pot of flavors and country backgrounds. Until the 18th century the country had been very sparsely populated, which dramatically changed with the influx of British convicts in 1788. After that, the borders have remained relatively open, even until now (provided you are not over 40), so many people emigrated to the country. As a result, not only are there a lot of British traces on the menu, Italian and other Mediterranean food is also widely available, as well as Asian food from many countries, which are relatively close.
Barbecue with mountains of meat is popular; a typically Australian dish would be kangaroo steak or just "roo steak"; even though here you can by ostrich, I have never seen kangaroo meat, apart from the can of kangaroo tail soup with which my mother tried to poison us in 1970 over Christmas. Furthermore, Australians have a sweet tooth and adore milkshakes, smoothies and cheesecakes.
Special days in Australia, on which you could serve these dishes, are 26 January, Australia Day; 25 April, Anzac Day (for Anzac biscuits); 3 June, Mabo day; 6 June, the Queen's birthday and 31 July, National Tree Planting Day.