MadCalc
MadCalc is a full featured graphing calculator application for your PC running Windows. With MadCalc you can graph rectangular, parametric, and polar equations. Plot multiple equations at once. Change the colors of graphs and the background. Use the immediate window feature to evaluate complex... Students can use it instead of that tiny calculator screen while you are doing your calculus homework. ... MadCalc provides all the essential graphing functionality without the complexity, cost, or overhead of something like Mathematica or MatLab.
http://www.madlogic.com/download/MC_INST.EXE - 387Kb - Download - Screenshot

DreamCalc Graphing Calculator
DreamCalc is the smarter alternative to a hand-held Graphing Calculator for your PC or laptop! You'll get the intuitive feel and productivity of using a professional hand-held, but one which adapts to your way of working. With DreamCalc, you'll be able to graph functions and plot list data more... Select from Reverse Polish Notation or two styles of algebraic input, and with the optional ability to run in your Windows system tray--DreamCalc will always be there whenever you need to reach for a calculator.
http://www.dreamcalc.com/downloads/dc3g_setup.exe - 3Mb - Download - Screenshot

Advanced Grapher
Powerful but easy-to-use graphing, curve fitting and calculating software. Graphs Cartesian (Y(x) and X(y)), polar and parametric functions, graphs of tables, equations (implicit functions), inequalities and slope fields. Up to 100 graphs in one window. ... Calculus features: regression analysis, obtaining zeroes and extrema of functions, intersections, derivatives, equations of tangents and normals, numerical integration, value tables, calculator. ... Supports English, Dutch, French, German, Italian, Portuguese, Russian and Spanish interfaces.
http://www.alentum.net/files/agrapher.zip - 1Mb - Download - Screenshot

DreamCalc Financial Calculator (Pro)
DreamCalc Professional is the smarter alternative to a hand-held Financial Calculator for your PC or laptop! You'll get the intuitive feel and productivity of using a professional hand-held, but one which adapts to your way of working. With DreamCalc, you'll be able to graph functions and plot... Select from Reverse Polish Notation or two styles of algebraic input, and with the optional ability to run in your Windows system tray--DreamCalc will always be there whenever you need to reach for a calculator.
http://www.dreamcalc.com/downloads/dc3p_setup.exe - 3Mb - Download - Screenshot

MathCalc
MathCalc run with the calculator and graph plotter mode. Within the calculator mode, you can compute mathematical expressions, trigonometric, hyperbolic or logarithmic functions. The entered expressions and functions are saved into formula lists. The program has a handy, easy-to-use formula... The graphs plotted, you can edit, save, print out and export to files of graphics formats (BMP, WMF or EMF). ... In addition, it is possible to export the graph points to a text file. ... MathCalc supports adjusting of all chart elements in the real time mode (WYSIWYG - What You See Is What You Get).
http://www.ypssoft.com/program/matce2_1.zip - 1Mb - Download - Screenshot

RORICX - Rate of Return Calculator
Calculates the Rate of Return and Net Gain for your portfolio (investment, real estate, rental, etc. ) Any time intervals, positive/negative RoR, regular contribution programs, individual transactions, combined (overall) portfolios, verification window for line-by-line review, graph, report,...
http://members.shaw.ca/lapides/downloads/roricx_download.exe - 605Kb - Download - Screenshot

BitMeter
BitMeter 2 is a bandwidth meter, it allows you to visually monitor your internet connection by displaying a scrolling graph that shows your upload and download speed over time. BitMeter is freeware - ie. it is given away completely free of charge, there is no trial period, no time-limited... Auto-start option for current user, or for all users. ... Speed/time calculator. ... Check for new version (with auto-check option and proxy support). ... BitMeter has lots of handy features: Statistics window, showing historical data both graphically and numerically.
http://codebox.no-ip.net/controller?page=bitmeter2dl - 1,011Kb - Download - Screenshot

Kalkulator
The Mother of all Calculators, a Swiss Army knife for scientists and engineers. Perhaps the most capable scientific/engineering calculator for Windows. On one hand, this is a calculator: evaluates expressions with more than 100 functions (trig/inverse, log/exp, statisical distributions, Euler,... Kalkulator has been evolving on various OS platforms for the last 15 years, being refined and polished through all this time, and its author has more than 25 years of active experience in numerical methods and software development.
http://www.wrotniak.net/works/kalkulator/_zip/kalkulator-inst.exe - 956Kb - Download - Screenshot

ESBStats - Statistical Analysis Software
Statistical Analysis and Inference Software for Windows covering everything from Average, Mode and Variance through to Hypothesis Analysis, Time Series and Linear Regression. Includes Online Help, Tutorials, Graphs, Summaries, Import/Export, Customisable Interface, Calculator, Live Spell Check,... - Comparison of Statistics for Raw and Grouped of the same Data. ... - Random Value Lists for Sampling. ... - Data can be Time Based for Time Series Analysis. ... - Data can be either for Sample or Population.
http://www.esbconsult.com/esbstats.zip - 5Mb - Download - Screenshot

Click Clock
Click Clock is a clock, calendar, weather, and astronomy program. It shows your local temperature in the tray. It also shows local weather, animated weather radar, animated satellite images, date and time of sunrise, sunset, moonrise, moonset, equinoxes & solstices, moon phases, eclipses, meteor... There is a clock and calendar for one month, and a calendar showing the entire year for any year. ... It displays a picture of the current moon phase in the program, on the task bar, in the tray, and in the window icons.
http://www.elegantpie.com/clickclock-setup.exe - 6Mb - Download - Screenshot