I didn't even know they existed until some years ago, I guess it's not usual in my country. The icons I was talking about are just cropping of random covers with faux funny titles to match (for instance, a cover with an old Nordic ship flying to the Valhalla through the rainbow and several other myth references, was dubbed "gay viking holidays")

http://iconzicons.livejournal.com/tag/book+:+choose+your+own+adventure