Is This a Tip?

I just started rereading Goblet of Fire, and after about ten pages, $12 fell out of my book and onto my chest, a ten and two ones.

what the fucking fuck? I have never in my life stored money in a book, nor used it as a bookmark. LOL what the hell.

on the other hand, this is better luck than I generally have even at the casino. Any ideas for what I should use my ill-gotten gains?