Other
Mystery Master: Logic Puzzles
Find several logic puzzle ranging from "very easy" to "very challenging."
Other
Juegos, Acertijos, Y Recreaciones Matematicas
In Spanish. A variety of logic problems, including puzzles and word problems with links to the answers. An excellent site to engage Spanish speaking students.
Ministerio de Educacion, Cultura y Deporte (Spain)
Centros5: Rincon Matematico 2000
Enjoy many of the math poems, puzzles and tricks in this math corner.