I was, of course, tempted to use Harlan Ellison's famous answer. Tired of hearing the same question over and over, he declared that every week he sent $5 (or $10 or $25, depending on the source) to a little old lady in Schenectady, New York and in return she sent him a list of ideas. Everyone laughed, but apparently at the end of the session there was a queue of people asking for her address.
I even thought of stealing Nick Tchan's recent forum post that said flying monkeys delivered ideas to him on scraps of paper.
Or Theodore Sturgeon's statement that every evening he left a bowl of milk on his front porch, and in the morning the milk had gone and a list of ideas had been left.
Instead I told the truth, that I see them everywhere around me. And they're coming faster than I can write them. I keep a list of them, of course. Some of these gems may not get used for a long time, some of them may end up as a minor idea in a different story. Some of them many never find a home.
Yesterday, for instance, I saw a car being towed by a tow-truck. I started asking "What if?", dropping the event into a number of different scenarios, and had half a story unfolding before I'd even realised it.
As for Theodore Sturgeon's answer, I think he may have been joking. At least once he suffered writer's block, bereft of ideas, and so he wrote to Robert Heinlein. Heinlein responded thus.
Check it out. It' a fabulous letter with everything from fully hatched ideas down to short, abstract thoughts.
