The visual novel medium is very much a niche interest in the West, but it's an extremely popular style of game in Japan.
It's growing in popularity over here, though, thanks to a combination of factors: the breakout mainstream success of visual novel and visual novel-inspired titles such as Ace Attorney, 999, Virtue's Last Reward and the Professor Layton series; an active fan-translation community; Western visual novel authors such as Christine Love and Georgina Bensley growing in prominence; and the long-standing, dedicated efforts of specialist publishers such as JAST USA and MangaGamer bringing the more "niche" (and often adults-only) titles to the West.
At the recent Anime Expo in Los Angeles, JAST USA announced a number of new localization projects, chief among which was the long-awaited Steins;Gate.
Steins;Gate, lest you're unfamiliar, is a well-regarded and popular science fiction visual novel featuring themes of the passage of time, time travel, and cause and effect. The player is cast in the role of Rintarou Okabe, an 18 year old self-proclaimed "mad scientist" and paranoid delusional. Okabe experiments with time travel and discovers that he is the only one able to determine the changes between different timelines -- a phenomenon he describes as "reading Steiner."
Gameplay in Steins;Gate is mostly conventional for the visual novel medium; you'll spend the majority of your time reading and listening to dialogue, and you'll occasionally have the opportunity to make a choice. Rather than a simple choice between two or three options, though, Steins;Gate's choices take the form of incoming phone calls that the player can choose to either accept or ignore. Okabe will also receive incoming text messages, and clicking on links in these messages will also trigger various choices, leading to one of several different conclusions.
Alongside Steins;Gate, JAST also announced localizations of a number of additional titles: life sim/card battle game Little Witch Romanesque; School Days spinoff Shiny Days; erotic dungeon crawler -- yes, really -- Lightning Warrior Raidy 3 (don't get that one mixed up with Lightning Returns when preordering); the fandisc for the utterly bizarre My Girlfriend is the President (the only game I know of in which you can have sex with an anthropomorphized spaceship); and two more titles called Sweet Home and Sumeragi Ryouko no Bitch na Ichinichi that I can't find a lot of information on but for which the cover art looks a little, uh, racy.
JAST hasn't released any further details about any of these games yet, and translating visual novels is often a mammoth undertaking due to the amount of text within. Stay tuned to JAST's blog and Twitter account for the latest updates -- be aware that JAST's site is very, very NSFW in a number of places!
If you're interested in the visual novel medium and not sure where to start, why not check out our recent piece on that very subject?