The most common question I get about writing is: "Where do you get your ideas?"
Nothing new there and no surprise I'm sure. My response is usually something like: "How do you not get ideas?" If the questioner is a fellow writer, we share a laugh. If not, I get to laugh (on the inside) while they stare at me wondering if I'm joking or not. Truth is, ideas have never been hard to come by. They're everywhere and come from the damnedest places sometimes. Open your eyes. Perk up your ears. Play with words and puns. Some of my best work has come from this sort of thing. Whether it's trapping a guy in a whale suit during the zombie apocalypse, a woman's ghost possessing a small clockwork bird, children chasing the bogeyman on a generation ship, or destroying the world with a teddy bear, it's all there.
I must admit most of my work to date has received its initial nudge from calls for submissions from various anthologies. I catch up with the calls through Duotrope, Ralan, or by chance. I immediately switch into humor gear. Every bad joke imaginable rattles through my head and who am I kidding, I don't switch into that gear. I live in that mode! All the ridiculous phrases and puns start me thinking about how I can fulfill the requirements but be as far out on the fringe of the theme as possible. The funny thing is, most of the resulting ideas aren't very funny by the time they solidify and I start writing. Amazing how close humor is to the very, very dark, isn't it?
Nothing inspires like a deadline too. Of course, my To Write list is now populated with half stories, bits of dialogue and pieces of description from a hundred anthologies that I was unable to submit to for various reasons. Still the pen scribbles on.
If you truly can't find an idea, google plot generator and you'll find an endless supply of prompts. All you need is the self-agreement that you'll run with whatever pops out.
My story "The Long View" from Martinus Publishing's anthology, The Temporal Element, is available free here as March 2013's Hit of the Month.