The BeholderBoard is a Perl script that lets you play chess with your friends (if you have a webserver). It was released as unsupported freeware in 1999, and it is now no longer maintained.
Download one of the following archives, containing script, readme and all the graphics (all in less than 48Kb!).
Install the script by following the instructions in the readme. If you're familiar with Perl in the cgi-bin, it's a doddle. Otherwise this script might not be for you.
If you like chess, you might like puzzles like those in Beholder's Planetarium.