Geogebra, an open source maths software
 

Geogebra, developed for education in secondary schools by Markus Hohenwarter at the University of Salzburg, is one of the most original and innovative maths software
currently available.
It works on a wide range of platforms and to used it on the pc you nead Java virtual machine which can be downloaded free following the simple instructions on the website www.geogebra.at .
The user student/teacher can use simultaneously a computer algebra system and an interactive geometric paper and so increase his metacognitive abilities.
The algebra input allows the user to generate new objects or to modify those already inserted and the work files can easly be published as web pages.
The 2.5.1 version doesn't have macros or complete help instructions, but the software is continually updated and improved.