A couple of months ago, a friend of mine, Deep, recommended SAGE to me. I installed it and played with it at very low level — solve a set of algebraic equations, plot some functions and generally use it as a calculator.But I did not pay much attention to it.
For the past ten days, I am trying to work with SAGE to solve a problem which involves some piecewise polynomials, their differentiation and integration (I will share the worksheet sometime soon on the net); I am having lots of fun with the software.
I remember discovering maple several years ago (again, thanks to two friends, Sai and Pradeep) one Saturday afternoon and enjoying it. After a long time, I am having similar fun with SAGE.
I think, SAGE is the best software I have seen after LaTeX in terms of its usefulness to my research and teaching, and I strongly recommend it to you!