The answer is generally disappointing, anywhere, everywhere, out of thin air!
I think a lot of people would like to believe that their is some magic formula that we have to use to invoke the muse to bring inspiration forth but the truth is it can be the simplest thing that can set the writers mind racing.
It could be a place or a photo, a person we see walking down the street or a snatch of conversation heard, sometimes the idea does just suddenly come into your head with no obvious outside stimulus at all. When you stop to consider the wealth and diversity of literature available then to narrow it down to any one way to be inspired really is an impossible task.
The one example of inspiration I do have is for one of the stories I working on right now and that was the strange noises coming through a thin wall between two bedrooms, there would be the obvious headboard scenario, but at times it was more like a body being dragged round the floor, or a ball being bounced off the wall the non writer in me just got annoyed at the noise but the writer started thinking of all sorts of plots and what if someone was in my place and got the wrong idea about what was happening, where could that lead and to what end.
If you would like to see more things that inspire me click on the picture to view some of my Pinterest boards but beware it does generally lead to lots of wandering round various boards before you notice the time and get back to what you were doing before you got distracted lol
So what inspires you or better still do you have a funny story which has inspired you?