The Magic Toybox , an interactive fiction game by Gareth Rees contains a mathematical puzzle related to quines and fixed points. Requires a zcode interpreter, which can be found at ftp://ftp.gmd.de/if-archive/infocom/interpreters/
There have been two IOCCC winners who have created 'near-quines'--for
lack of a better term. These programs
contain data which change from compilation to compilation. So here's a Tic-tac-toe program, and a program to play Conway's Life.
Would you believe a universal quinnificator? I haven't really taken a good look at this, but it claims to turn any valid C program into a quine...
Here's a java library to aid in quine-making.
Once again, I haven't really given it a look.
From the author, Daniel Lyle:
While the following Quine is lengthy, it is easy to write using the
following utility class I wrote , which is enclosed entitled
"ConvertToPrintChar". I ran this using the JDK 1.2 version of Java (a command line compiler) in a Windows environment and used the command form: " java ConvertToPrintChar > runlog.txt " to pipe the programs output to atext file that I could easily cut and paste from. The System.in.read() function assigns a -1 to the int variable charn when the user presses <cntrl - Z> to signal that he/she is done with entering data.