Wikipedia
Archimedes-lab.org is a free and collaborative edutainment project developed and maintained by Gianni A. Sarcone and Marie-Jo Waeber, two authors and writers with more than thirty years of experience in the fields of visual thinking and education. This educational project is part of the Open Education Consortium and it is supervised by a consulting network of experts specializing in online education.
The main goal of the web site is to teach mathematics differently and to make it accessible to everyone through visual puzzles and games. The site walks visitors through various problem solving strategies and discoveries in the world of recreational mathematics.
Limited parts of the site are offered in French, Italian, Spanish and German. But regular puzzle features like the Puzzle of the Week, the Sunday Puzzle and the Puzzle of the Month are available in three languages: English, French and Italian.