Math.com
Computer Romanus: Roman Numeral Calculator
This site has a calculator that uses only Roman Numerals! There is also an explanation of the number symbols for reference.
Teachnology
Teachnology: Math Lesson Plans
Great lesson plans covering a wide-range of math-related subjects.
Purple Math
Purplemath: Solving Polynomials: How To
Demonstrates the steps involved in solving a general polynomial, including how to use the Rational Roots Test and synthetic division. Points out when using a graphing calculator can be very helpful.