GraphCalc

GraphCalc is an open-source computer program that runs in Microsoft Windows and Linux that provides the functionality of a graphing calculator.
GraphCalc includes many of the standard features of graphing calculators, but also includes some higher-end features:

High resolution
* Graphing calculator screens have a resolution typically less than 120×90 pixels, whereas computer monitors typically display 1280x1024 pixels or more.
Speed
* Modern computers are considerably faster than handheld graphing calculators
Three-dimensional graphing
* While high-end graphing calculators can graph in 3-D, GraphCalc benefits from modern computers' memory, speed, and graphics acceleration

GraphCalc was developed by Brendan Fields and Mike Arrison, computer science students at Bucknell University, before graduating in 2000. Mike continued the development briefly from 2001-2003, but has since abandoned the project. Other similar projects being maintained are KAlgebra and Cantor.