The Tunguska Event figures prominently in the new Thomas Pynchon novel. It occurs while many of the main characters are in Siberia. Mystical cities re-appear for a short time and strange characters walk the earth before fading away again. The fictionalization certainly leaves the cause unanswered but many of the details are subtly explored. It was some of my favorite stuff in the book.

As usual, Wikipedia kicks ass - they even have a link to the evnt being mentioned in fiction, including the one I just read. What an incredible resource.