This thread is for the discussion of translated or semi-translated Visual Novels. KS is in it's own thread. Monster Girl quest and similar eroge games are welcome, but please use http://catalog.neet.tv/vg/ to check for separate ones.
FAQ:
Q. What is a Visual Novel?
A. A visual novel is essentially an interactive story book. They cover a wide variety of genres, but many are set in a high school.

Q. Visual Novels aren't games, this is for Vide-
A. Fuck off.

Q. Where can I download such Visual Novels?
A. There are many websites.
http://vndb.org/
http://erogedownload.com/
http://bitgamer.su
These should point you in the right direction. If not, use /jp/'s server.
ftp://jpftp.mine.nu/
Username is Anonymous (remember capital A)
Password is /jp/
Please be aware that said FTP server is run by a single person on their home connection and should not be used unless all other options have proven unfeasible.

Q. I want to start reading VN's. Which Visual Novels should I start out with?
A. There are a few entry level VN's that everyone interested in the genre should read. Yume Miru Kusuri, Saya no Uta and Katawa Shoujo, but take that crap into their own generals until they get bored. These give a rough idea of the genre and how it works. From that, you can try all sorts of VN's like Majikoi, Clannad, Ever 17 and if you're a bad enough dude, you can read the Muv-luv trilogy. The VN database is useful, as it can tell you which VN's are translated, which VN's are the highest rated, and you can even look to find specific things in a VN with the tag function. You can find what YOU want the better than any of us.

Q. Muv Luv Extra is just boring harem crap, can I ski-
A. No, stop asking.

Q. Can I talk about the ends of VN's?
A. Yes, but use spoilers. Dear god, use spoilers.

Q. People aren't talking about the VN's I like!
A. Then you try talking about them. Don't expect threads to go into Muv-Luv discussion if Majikoi just released a new translation or something.

Q. Can I talk about this awesome crazy new VN I'm developing?
A. Yes, but actually come with something presentable in hand. A mere idea, or even some pastebin with walls of text won't convince anyone unless you're THAT good (which you aren't).

Q. Nigga dis shit all in Japanese
A. Yeah, most VN's aren't translated. The ones we talk about are, or are at least in the progress of being translated.
There are however quite a number of people in the threads who know enough Japanese to read (and discuss) untranslated VN as well.

Q. How do I learn Japanese well enough to read or even translate Visual Novels?
A. Read this http://pastebin.com/KaWcfU4K and start participating in the Daily Japanese Thread on /a/.
You will eventually start picking up runes as you read, making VN an ideal learning tool.

Q. The VN I installed gave me an error/text didn't display correctly!  What do I do?
A. Well, this could be any number of things, but before asking us make sure to run both the VN and installer as an administrator, and to set your system locale to Japanese before installing.  Don't bother with AppLocale, it just introduces new bugs and for the most part there's no reason not to just leave your system in Japanese locale.  Most English programs aren't as finnicky as Japanese ones for whatever reason.

Q. How do I change my system to Japanese locale?
A. On Windows 7, this option can be found in the Administrative tab of the Region and Language submenu on Control Panel.  The option you want to be changing is "Language for non-Unicode programs"  In XP, this can be found in the Advanced tab of the Regional and Language options submenu in Control Panel.

Above everything, try to enjoy yourselves, oh put the effort in spelling and grammar when you talk.
"Halp plz i R dum" will not inspire a great deal of helpfulness in the hearts of most Anons.