I first learned about the page 99 test from William Gass (I’ve forgotten where) who I think got it from Ford Madox Ford: “Open the book to page ninety-nine and read, and the quality of the whole will be revealed to you.” Sounds like a fractal approach to literary theory to me.
So, from Gass’s The Tunnel:
The dust then. It slid through the crevices no ant could crawl through, sifting under doors to wedge them shut. It appeared like a sudden rush on polished tables, threw gloom in mirrors, begrimed the beds and grayed the linen, clung to drapes and curtains, filmed milk, sanded flour and sugar, and coated all uncovered food with its special granular display. On the other hand, the sky on hot dustless days would leap with light, nails would wink in their boards, pails blaze like beacons, and the glass of the several stores would shout the sun at you, empty your head through your ears with whistling sunshine.
Have you ever tried this test? How about giving us a quote from your favorite page 99?