The current release is Release 2.
Party Zcode File (the game itself)
Party Source Code File (for use with Inform)
Inform (used to make the game)
You can also find links to interpreters other than Frotz on this page, along
with lots of other interesting links.
Frotz (needed to play the game)
WinFrotz (Windows version of Frotz)
The Party chapter itself, hosted by ImproFanfic