I made a raisin through neglect! In my car!
I was road tripping, and my girlfriend was feeding me grapes. (it sounds romantic but it was actually just a way to save time by cutting out the rest stops for meals.) and she missed my mouth and the grape tumbled somewhere beneath my seat.
Several weeks later, when I finally took all my stuff out of my car, as I was cleaning up, I remembered the grape and went to look for it, fearing a giant mass of blue mold fuzz. instead I found a perfect raisin, tucked away by one of the supporting struts of the front seat.
So in case any of you are wondering how to make raisins, apparently leaving some grapes in your car over the summer with the windows up will do it, even if the grapes are in a dark location.
Now you know.