FreeMat is a free environment for rapid engineering and scientific prototyping and data processing. It is similar to commercial systems such as MATLAB from Mathworks, and IDL from Research Systems, but is Open Source. FreeMat includes several novel features such as a codeless interface to external C/C++/FORTRAN code, parallel/distributed algorithm development (via MPI), and plotting and visualization capabilities.
MU Staff! At Source Forge and the dev website, 4.2 is the latest release and the release date is June or July, 2013. See: https://sourceforge.net/projects/freemat/files/FreeMat4/
and: http://freemat.sourceforge.net/#news
Wow that's pretty cool. My needs are pretty trivial, but this seems to cover them. My only beef is how ugly the scroll bars are, and also it feels slow. The slowness seems to be in the drawing, since it does begin writing the answer to screen almost immediately but each line has a quarter second noticeable delay.