http://www.thechineseroom.co.uk/esther.htm
In a word, brilliant. Little wonder this mod won awards...
I'll say that much and highly recommend it - no spoilers.
Dear Esther is a Half Life 2 mod, and as such requires a
fully installed and working Half Life 2 installation. I
test this title with Steam/The Orange Box.
This mod does not come with an installer - to install this
mod, simply download the .zip file, and unpack it's contents
into the following location (linux path shown);
~/.cxgames/[bottle_name]/drive_c/Program Files/Steam/steamapps/SourceMods
When you restart Steam, the mod will show up in your list
of games - play the mod.
Cheers!