In the US the farmers' markets get set up once or twice a week if we're lucky to have any where we live.
The Karmeliter market, just across the Donau (Danube) from the center of Vienna, is open every day and when we lived just a couple of blocks away it was a treat to be able to buy fresh-picked produce as needed.
Wonderful bread, cheeses, flowers, fruits, eggs, organic foods -- everything you can get in the Naschmarkt but without the crowds and traffic -- on Saturdays when all the shops are open and the stands are set up.
Great place to shop and, unlike US farmers' markets, the prices are usually better than at supermarkets.
And if you don't live nearby, you can always stop for a meal at one of the places in the area --- the Fliegender Holländer (Hollandstr. 8) comes to mind. read more