Presuming that AD&D 2E isn't too recent to be considered a "classic," I'll say that I think Lisa Smedman's
S5 The Dancing Hut of Baba Yaga (affiliate link) is a superb adventure. The backdrop is fascinating for what it presumes (e.g. that various forces - such as Day, Night, and Twilight - have incarnations that can be interacted with), the adventure is thrilling for its scope (the Hut is "funhouse" dungeon, but with its own underlying theme), and Baba Yaga herself is an awe-inspiring character. I honestly can't recommend this one enough.