I personally know of a couple of conspiracy theories that my octagenarian aunt has told me about which took place in those decades. She had a very long career as a real estate agent at a time when women were very rare in that type of work. Firstly she told me that she once went to a restaurant in the late sixties and was sitting at a table next to a very long table full of young people and an older man with a thick Rusian accent. She over heard ( or was eaves dropping) what the Russian man was saying. He was arranging and organising protests and all the younger people were in on it. Is it possible that all those protests that happened in the 60s & 70s were a communist conspiracy? Perhaps they were behind the protests in the USA too. A lot of those protests were anti- war & had an impact in the Vietnam withdrawl. Secondly, and I know this sounds far-fetched, but my Auntie Jenny also believes that vegemite is really made of Mount Gambier rock. She told me she once went to a vegemite factory and all these rocks were getting crushed up in to a powder to be be made into Vegemite.