Here's an amusing toy: I Write Like. Drop a few paragraphs of your text in there, and it claims to analyze it and tell you what author matches your style. Of course, I seldom write like anything at all these days, but that's beside the point. My old Illinois River piece yielded up David Foster Wallace (doesn't mean much to me); my more recent discussion of tamarisk beetles gave Nabokov (thanks, but I don't think so); but my Gila River trip report yielded what is surely the correct answer (Iä ! Iä !)
The first five paragraphs of Call of Cthulhu gets you Arthur C. Clark. A few more paragraphs got us there, but "cyclopean" was a dead giveaway.
Via Atomic Nerds (sorry about the Atwood).