Visual novels are, essentially, choose your own adventure books with pictures and music. And most of the time they're at least partially pornographic, but with the best of them, you pretty much skip over the porn. For some reason they're categorized as games.
A lot of VNs get turned into anime, especially nowadays, with studios more desperate than ever for source materials to adapt. Fate/stay Night, Amagami SS, MajiKoi, Clannad, etc. Even though the numbers aren't quite up there with the manga and light novel adaptations, they're still pretty high. (No, the porn does not get animated.)
"Gameplay."
Most visual novels are about choosing a girl you like and trying to court them with cheesy preselected dialogue. The aforementioned Clannad, most VNs by Key, Yume Miru Kusuri... er, it's actually not worth listing them now that I think about it, as exceptions are very hard to find (Ever17, for example). But even when they take this decidedly otaku-pandering route, they can fit in themes to make it interesting, or put the romancing bullshit on the backburner. YMK, for example, explores the issues of Japanese school bullying, teen pregnancy, and drug abuse in its three routes. Kana: Little Sister is supposed to be really depressing, though I haven't gotten to it yet. And FSN is basically an action series, so much so that it has spawned two fighting games, an RPG, a totally badass prequel, and a movie that is basically fight scene to fight scene. Over the course of the 60 hours it takes to read its three routes, maybe 5 is not spent on plot progression.
But I won't try to convince you to try them. 90% of the medium is trash like this:
Wanko to Kurasou, where dogs are people and you have to fuck them when they're in heat.
There's good stuff here, though, and I'm not ashamed to like those ones. No better way to close out the semester.
Some of the, uh, stellar writing typical of VNs.
