Windows AGiliTy is an interpreter for the old Adventure Game Toolkit (AGT). Although
considered outdated and little used these days, AGT was popular in the late 1980s,
and a community centered around Compuserve (a commercial bulletin board system
popular before the Internet really took off) wrote a large number of games with it.
Of these games a few are still worth playing, such as Compuserve and
Shades of Gray.
Windows AGiliTy is a port of Robert Masenten's AGiliTy, a reverse engineered interpreter
that can play games produced with any of the many versions of AGT.
The current version, Windows AGiliTy 1.1.1, can be
from the IF-Archive, as can quite a few games.
For ratings and descriptions of these games,
search for AGT games at IFDB.