My wife recently got Kombucha mushroom from a friend, and got into fermenting it herself. Its trivial to do, you need to really screw up something for it to go wrong, tons of good bacteria inside. She takes some basic precautions like avoiding metal parts (since the drink becomes acidic), otherwise its on autopilot, good bacteria outcompete everything else for resources.

She mixes it with some cut fruits to get some sugars for fermentation, the result is very mild alcohol content (maybe 0.5%) and it tastes like cider. I mix it maybe 1:3 with water and its semi-eternal homemade drink. Can't really complain.

That and of course french cheese, we live maybe 5km from French border and for cheese its much better place than even Switzerland (sorry guys gruyere is great but french variety is huuuuge in comparison and they even usually have specialties like old dutch gouda which is taste heaven for me and various truffle-infused ones).