The text and its layers of footnotes are formatted to make the reading experience mirror as much as possible the experience of the characters. When the characters are lost, confused, and trudging slowly through the maze, the text is heavily footnoted and the footnotes are arranged on the page so you have to turn the book constantly to read them. When the characters are running, there are few words per page, meaning the faster they are moving, the faster you are turning the pages. House of Leaves is an often overwhelming, but always compelling, testament to what is possible with the written word. Which makes choosing the next book almost impossible. Here are a few books that expand on, or are written in the spirit of House of Leaves.
The first book I recommend when I find out someone has read and enjoyed House of Leaves is The Raw Shark Texts by Steven Hall. The novel starts with Eric Sanderson waking up in shock, not knowing where or who he is. Soon he starts getting mail from himself that explains he is plagued by a Ludovician, an information shark that eats his identity. The story then follows Eric's attempts to recover his identity, connect with his past, and conquer the shark. Information theory, code breaking, adventure, romance, Jaws references. The Raw Shark Texts is a brilliant exploration of our information driven society that manages to also be a ripping yarn.
The Way Through Doors by Jesse Ball is a modern fable that dispenses with chronology, narrative conventions, and page numbers. Selah Morse, a "municipal inspector" sees a young woman struck by a car and though she is unhurt, she suffers amnesia. Selah assumes the role of her boyfriend, takes her to the hospital, and then tells her stories to keep her awake for the night. The stories twist around each other, double back and start again. Characters are revisited and transformed. What might be the most remarkable thing about the book, is that despite appearing so post-modern, it maintains a tone and atmosphere of our oldest legends and fairy tales.
Important Artifacts and Personal Property from the Collection of Lenore Doolan and Harold Morris, Including Books, Street Fashion, and Jewelry by Leanne Shapton is a novel in the form of an auction catalog. Through the objects and the descriptions of the objects Harold Morris and Lenore Doolan's entire relationship is narrated. Not only does the novel explore our relationship to the objects in our lives, it also asks the questions: what are stories made of? and what are characters made of? The most remarkable thing about the book, though, is that, despite just being a detailed list of stuff, it feels like a regular story and it ends with a profound feeling of closure.
Along with these three books, there are a couple that I've seen, but not read, that draw from the freedom of format demonstrated by House of Leaves. The Annotated Nose by Mark Estrin and Personal Effects by J. C. Hutchins.
And if none of these work for you, there is always Danielewski's second novel, the National Book Award finalist Only Revolutions. It is a very different book from House of Leaves, but I think it's just as good.