Where do you get your ideas?

The answer to this most cliched of interview questions asked of SF authors is, of course, Robert Heinlein. At least for Theodore Sturgeon, it was. In a Guest of Honor speech at a SF convention, Sturgeon recounts an instance of writers block:
I went into a horrible dry spell one time. It was a desperate dry spell and an awful lot depended on me getting writing again. Finally, I wrote to Bob Heinlein. I told him my troubles; that I couldn't write-perhaps it was that I had no ideas in my head that would strike a story. By return airmail-I don't know how he did it-I got back 26 story ideas. Some of them ran for a page and a half; one or two of them were a line or two. I mean, there were story ideas that some writers would give their left ear for. Some of them were merely suggestions; just little hints, things that will spark a writer like, 'Ghost of a little cat patting around eternity looking for a familiar lap to sit in.'
And now Letters of Note has reproduced the entire Heinlein letter in question, complete with all 26 ideas and amusing banter ("To have the incomparable and always scintillating Sturgeon ask for ideas is like having the Pacific Ocean ask one to pee in it.") Also, funny how they refer to each other as Bob and Ted. Heh. Anyway, here's some of my favorite story ideas:
a society where there are no criminal offences, just civil offences, i.e., there is a price on everything, you can look it up in the catalog and pay the price. You want to shoot your neighbor? Go ahead and shoot the bastard. He has a definite economic rating; deposit the money with the local clearing house within 24 hrs.; they will pay the widow. Morality would consist in not trying to get away with anything without paying for it. Good manners would consist in so behaving that no one would be willing to pay your listed price to kill you.
Heinlein notes that this is more John Campbell-ish than Sturgeon-ish, but this idea is actually quite Heinleinian. The letter was written in 1955, but you can see a lot of these sorta proto-libertarian ideas, even this early in his life. Another idea:
The bloke sells dreams, in pills. Euphoria, along with your fantasy, is guaranteed. The pills are not toxic, nor are they harmful the way narcotics are, but they are habit-forming as the euphoria dreams are much better than reality. Can the Pure Foods & Drugs people act?
That one is pure Phillip K. Dick (Heinlein and Sturgeon would probably call him Phil). More ideas:
We know very little about multiple personality, despite the many case records. Suppose a hypnoanalyst makes a deep investigation into a schizoid...and comes up with with the fact that it is a separate and non-crazy personality in the body, distinct from the nominal one, and that this new personality is a refugee from (say) 2100 A.D., when conditions are so intolerable that escape into another body and another time (even this period) is to be preferred, even at the expense of living more or less helplessly in another man's body.
Reading a letter like this, while appreciating the generosity, I can't help but think that it's not really the ideas that matter. These are all fantastic ideas and Heinlein is brilliant here, but we all have great ideas. Ideas are important, but perhaps not as important as we like to believe. You still have to deliver on that idea, which is harder than it looks and that's also where the likes of Heinlein and Sturgeon made a name for themselves. Conversely, there are folks who manage to take dumb ideas and make them into something profound. It's all in that process that the magic lies. Ideas are easy. Heck, I have my own SFnal idea about multiple personality syndrome. But do I have the stones to do anything about it? Well, it is NaNoWriMo... Only 2 days left, but who knows?