Here we go again

Imagine someone came to you tomorrow and asked "I want to play adventure games, can you recommend 20 games to play". The purpose of this thread is to provide the answer.
It isn't meant to be a list of the 20 best games of all time. It isn't meant to be Adventure Game 101. It might end up being both those things, but first and foremost it is a list of games that you would recommend to someone else to play.
For that reason, you might not include something that is notoriously difficult to get to run, or which has clunky graphics by today's standard, or has no sound apart from a tinny midi soundtrack. You might not recommend a game that you found awesomely wonderful on the basis that no one else has your particularly strange sense of appreciation. You might not recommend every Myst clone you have ever played because even though they are your passion, a whole list of them might be, well, a little dull.
Or you might - many players have old game rigs and there are numerous programmes that help get old games to run on new machines, who said you need flashy graphics to tell a good story, and perhaps elaborate soundtracks simply cover up the flaws in a bad script. There might be someone out there just like you who doesn't know about your awesome game, and too many Myst games is actually never enough.
The point is its up to you - if you think a game you have played is worth recommending to someone else to play, you can put it on your list.
So long of course as its an adventure game. And we all know what they are. Quake isn't one, however beautifully scripted it might be, but Myst is. Somewhere in between is a grey area which doesn't matter between friends, which we all are.
There are some rules though:
1. You can recommend a maximum of 20 games. You can choose to recommend less.
2. You cannot recommend a series. If you want to recommend all the Tex Murphy games, that will take 5 seperate recommendations, one for each game.
3. The following episodic adventures will be counted as one game - Sam & Max Season 1, Sam & Max Season 2, Wallace & Grommit, Strong Bad, Casebook.
4. Myst and RealMyst will be counted as one game.
5. Uru and its add ons will be counted as one game.
6. BadMojo and the Redux version are one game.
7. Directors cuts will be counted as the same game.
8. Adventure games only please (Dark Side games and Casual games get their own lists).
If at all possible, please list in alphabetical order - it makes counting so much easier. In doing so, ignore "the" (so The Lost Crown would be under "L" for Lost)
The thread stays open for about 3 weeks, and I will post updates as we go. Also, avoid editiing your lists after posting because I count as we go, and may miss a change.
So who wants to be first?