Bring the Jubilee, or a new branch universe, as in Roswell, Texas (full disclosure — I'm one of the writers), that coexists with the original timeline. And then we have stories that don't involve time travel at all, but are just about parallel universes that coexist with ours and are based on the "many worlds" theory of quantum physics. Two good rationales for a lot of good (and sometimes bad) fiction.
In Hayford Peirce's two-book series, we have both. And we have a lot of fun. Really funny science fiction is rare, and funny science fiction in the alternate history subgenre is even rarer. Most of it is dead serious, sober stuff. I think of Poul Anderson and Philip K. Dick and Keith Laumer, whose alternate histories are all very good, but the comedy isn't there. (Oddly, Keith Laumer's Retief stories, which are standard SF, are very funny.) Other than Peirce, the only consistently funny alternate history author I can think of is the irrepressible L. Neil Smith, whose stuff I'll be reviewing later.
Well, already I digress. Napoleon Disentimed is a picaresque story about a semi-lovable con man, calling himself "The MacNair of MacNair," who wanders out of our universe in a comical way into a world where Napoleon I won all his wars, and Napoleon V rules Europe and is in a cold-war relationship with a powerful Ottoman Empire. MacNair locates his doppelgänger (and conspires with him semi-successfully) in that universe, and also funny mad scientists and even Napoleon V himself, who sort of reminds me of the Austrian Emperor in Amadeus. Hilarity ensues, with time-travel back to the era of Napoleon I in that universe, and we alternate history veterans suspect that such travel will somehow eliminate the timeline and result in ours, as is so often the case, but that doesn't exactly happen. But no spoilers here. I'll just say that jeweled crowns and flush toilets and Easter Island are involved.
The Burr in the Garden of Eden is even more picaresque and bizarre, and we're treated to a meeting with the alleged Napoleon wannabe, Aaron Burr, who we haven't been able to read about since Gore Vidal's Burr and Michael Kurland's The Whenabouts of Burr (both good reads, BTW), and he's just as amusing and confusing as ever, and maybe more so. Snarky comments about Thomas Jefferson add an air of political reality to the story. MacNair is also present, having wandered into this third timeline in an equally comical way, both sideways and backward in time, and we also meet a rambunctious Davy Crockett, who is always a pleasure. Other features are a Black republic in Utah, a weird religious cult in Louisiana, Sally Heming's grandson or great-grandson, I can't remember which, and Harry Truman.
These are both currently available from Amazon, but hard to find otherwise. If you like alternate history and funny stuff. You're in for a treat. Enjoy. — Rex F. May