Alternatives to a "traditional" textbook genre? Story-telling didactic "texts"

Number Stories and Storytelling

David Eugene Smith's Number Stories of Long Ago (1919)
Hans Magnus Enzensburger's Number Devil
Freudenthal Institute and story paths: http://www.nap.edu/openbook.php?record_id=12519&page=175

Ron Eglash's page on African Fractals

Puzzles and "recreational mathematics"

Sam Loyd's Cycopedia of Puzzles
David Suzuki's video tribute to Martin Gardiner

Toshikazu Kawasaki's Roses, Origami & Math

 "Coloring Books" that foster investigations: 

Excerpt from Herb Kohl & Winky Adam, Insides, Outsides, Loops and Lines
click for excerpt

Literature as Classroom text(book)?

Pat Hutchins, Clocks and More Clocks

Anno's Mysterious Multiplying Jar
Anno's Magic Seeds
Rod Clement's Counting on Frank
Denis Guedj's The Parrot's Theorem
Sarah Flannery's autobiography, In Code: A Mathematical Journey

Passover Haggadah as Ur-Text 

Alan Block, "Even if we were all scholars: The teacher's authority"

Landscapes, Soundscapes, ...

UBC Orchard Garden 
Marta Civil, unearthing the mathematics of a classroom garden (working paper on-line, later published in another form as Kahn, L. & Civil, M. (2001). Unearthing the mathematics of a classroom garden. In E. McIntyre, A. Rosebery, & N. González (Eds.) Classroom Diversity: Connecting School to Students' Lives (pp. 37-50). Portsmouth, NH: Heinemann.)

Breaking away from the math book (Pat Bagget & Andrzej Ehrenfeuch)