A challenge among European students to reconstruct some "Crop circles" formations using Geogebra (a free maths software), not too difficult and very intriguing. This is the first step for a partnership, the schools involved will be able, of course, to develop and create materials on other subjects and also involving the colleagues of other subjects such as science, chemistry and physics. The open source software GeoGebra (www.geogebra.at) from the University of Salzburg is used in many schools throughout Europe (more than 70.000 downloads in 2005). Geometry, algebra and calculus are joined in GeoGebra in an innovative way in order to give pupils and students a more active role in learning mathematics. Today, GeoGebra is available in 13 languages and some of the translations are the result of cooperations with the promoting schools. Teachers from all over Europe use and contribute to the multilingual user forum (www.geogebra.at/forum) and the multilingual pool of educational materials (www.geogebra.at/en/wiki) around GeoGebra. The innovative combination of geometry, algebra and calculus in GeoGebra makes its resources easily transferable to many domains in mathematics and other subjects. The network Com@net wants also to take advantage of the multilingual resources of GeoGebra (www.geogebra.at/wiki and www.geogebra.at/en/wiki) that allow European students and teachers to collaborate in an innovative and very useful way.