This is a script I wrote a few months ago that someone might find use for, if you happens to enjoy good old static gamebooks (CYOA, if you insist on calling them that) and have stumbled upon one of the (too many) PDF gamebooks that do not have any embedded links. It is quite tedious to have to search up and down a big PDF to find the paragraph you are looking for. Unfortunately my heuristics sometimes need a little help (see README), and on some books do not work at all, but most of the time it manages to find the paragraphs and add the links. Turns a static PDF into something that is almost playable as a real computer interactive fiction game (well, you still have to roll dice and write things down in a character sheet or whatever).
(Two links self-promoting my tools. That was all. Done for now.)