There are two main
high-level programming languages in use by modern
authors of Interactive Fiction;
Inform and
TADS. There are also several lesser-used
languages, such as
AGT and
Hugo. All of these
systems are
customized specifically for
writing adventure games in a
text-based environment.
There is an archive of free Interactive Fiction games (as well as interpreters, walkthroughs, maps, compilers, etc.) at ftp.ifarchive.org
There is also a yearly competition held for newly released Interactive Fiction games; the voting period usually begins at the beginning of October and extends until mid-November.