Windows

ANS Forth Chess
Very simple, free chess program written in ANS Forth, by Jeff Fox of UltraTechnology.
http://www.ultratechnology.com/chess.html

JohnGin Chess
Offers a screenshot, game description, and download.
http://www.sweb.cz/johnginsachy/Eng/

Parmen's Page
A Star Trek variant.
http://www.hemptrek.com/parmen/parmen.html

Victorian Chess Pages
This page has demo versions of several chess related programs written by Fide Master and ex Australian correspondence champion Bill Jordan.
http://home.vicnet.net.au/~chess/programs.html