I am a bit of a King Arthur aficionado. My tastes seem to be for pretty classic...um...classics. I like King Arthur, Sherlock Holmes, Superman, Elvis Presley, Bruce Springsteen - just to name a few.
Anyway, I ran across a book in a used book store (Pauper's Used Books in Clayton, NC) entitled "Arthur War Lord" by Dafydd Ab Hugh. Without even googling Dafydd Ab Hugh, I believe I have read a Star Trek novel by him but I can't swear to it so I couldn't say for certain how skilled he is as a writer (yet). The book though is a cross genre piece, which I enjoy. I enjoy crossing genres when it is done poorly (like Jason X) but I REALLY enjoy it when it is done well (Like the Valley of Gwangi). So, this book combines time travel and King Arthur in a way that is a bit more sci-fi than "A Connecticut Yankee in King Arthur's Court".
For fans of time travel and/or King Arthur, it is probably worth a look.