Melbourne has their annual Open House program (http://moh.org.au/)
I think Adelaide should have our own Adelaide Open House, which unlocks the city for few days/weeks a year, allowing anyone to explore visit buildings/places which are off-limits to the public most time of a year.
Adelaide is proud with her churches and much more heritage buildings as well as cutting edge contemporary architecture, by having this Open House for Adelaide, I think it will inspire everyone and promote idea-led or design-led lifestyles, thus creating a more vibrant city. Who doesn't want to have something attractive and pleasure to see? The Guggenheim Bilbao Museum successfully put a previously unknown city to the world map, and I think we could have one in Adelaide and bring the city to be on par with other capital cities in Australia.