I suspect a large minority of people here have read at least one Harry Turtledove novel (and if it's Guns of the South or anything earlier than that, you might have even enjoyed it), so we're probably familiar with the idea of alternate history; though Escape Pod doesn't see all that much of it (the only ones I recall off the top of my head being "The Eckener Alternative," and "Night Bird Soaring"). That might be partly due to the tendency toward preachy, incoherent novel-length essays on libertarianism, or "OMG guys, what if the Nazis won?" Congressional book deals. I dunno.
There are a lot of alternate history, and the related Connecticut Yankee-type modern man in an anachronistic setting sorts of books, but AFAIK they tend to tread the same ground, or the same sort of ground over and over again, despite hundreds of commonly known possible turning points, and probably millions of lesser-known ones.
What are some alternate history concepts that you think could be interesting, but which as far as you know haven't been done? How do you see it playing out?
For all the "what if the Nazis won?" talk, or other variants (Worldwar, for example), I don't know that I've ever heard of a story considering what if the Nazis had never risen to power. Would the elements in the US and Britain that sympathized early on have driven the US and UK to wear the black hats? Would WWII have happened anyway, only with the USSR?
Or getting the hell away from the only history the Alternate History reading public knows (America's big wars): What if the Ainu/Emishi hadn't fallen, and advanced apace with the Yamato? Imagine another state in the north Pacific, on Sakhalin and Hokkaido. Maybe a weaker Russian far east, as this state courts the ethnic groups of that region. Maybe a stronger one as Russia devotes more forces to the region due to the presence of a power with more interest in the Sea of Okhotsk than Japan ever had. Animal rights groups would be protesting the Ainu treatment of bears instead of or in addition to the Japanese's treatment of whales. Maybe Yamato never gets its expansionism rolling on into the modern day having not had the history of success in the north to give them the experience and confidence to walk all over the Asian mainland.
What if all that happened because Baekje defeated Silla in Korea, rather than the other way around, and the technology and culture of the fleeing Baekje refugees never invigorated (or founded, depending what view you take) the Yamato state in the first place. Then you've also got a more strongly independent Korea; but one that is a more likely to end up in conflict with China and the Jurchens, so may be less likely to survive to the present day. Also, they'd be speaking a different, though probably recognizable if not intelligible, language. And the Japanese language as we know it wouldn't exist either.
What if the Lewis and Clark expedition had made it far west, but been lost and never reported back? How much would that have delayed American westward expansion? What opportunities might that have afforded the British, the Spanish/Mexicans, the Russians, and in particular the natives of the west (who would suddenly have an advantageous information asymmetry, if nothing else in their favor) to consolidate their positions?