From David Eppstein - Myriad articles and links about recreational mathematics, with broad appeal, a site for all and sundry... If you don't know what you are looking for go here, you will find it!

Lee Stemkoski's 'Mathematrix'...Polyominoes, Higher Dimensions, Rubiks Cube, Flexagons, Fractals, Mobius strip, Non-Transitive Dice, Life, Tangrams, Constants, Math Humour and more...

efg's Computer Lab - Fractals and chaos - Programs to play with and download...

David.J.Eck's mathematical java website. Contains many sample programs with source code, as well as a very useful java tutorial with an introduction to programming. It features an elementary pentomino solver.

Paul Bourke's introduction to fractals, an overview and starter guide.

RIP - Birger Nielsens eclectic site no longer in existence. Self styled as a "Drinker of Tea", he used to have many math pages; this once was a link to his page on Lindenmayer System fractals. All the methods and Perl source code for producing them used to be there. It was written in Danish but surprisingly readable all the same. It was an excellent source of new ideas.

Jacobo Bulaevsky's tutorial for producing L-system based fractals. A site for for children (and any adults who learned their math in the dark ages of education) who want to find out, or need a basic primer on the subject.

Stewart.R.Hinsleys website amongst many things it is an excellent site for discoveries in IFSs (Iterated Function Systems).

Arnold Reinders has written a shareware program that is adept at turning fractals into music, with some extraordinary reults...The program can be downloaded by adventurous cyber-musicians. There are also some sample files produced by users of the program that can be listened to.