Mac OS X only: Mac users envious of Windows 7's new souped-up built-in calculator can take solace in Magic Number Machine, a free, advanced graphic calculator for OS X. Features include 25 digits of precision, hexadecimal, binary, decimal and octal display including fractional, scientific notation and negative numbers in each, complex numbers, array functions, and a whole menu of scientific constants. It's been a long time since I've needed a calculator this advanced and complex, so mathletes and scientists, let us know how it is. The Magic Number Machine is a free download for Mac only. Thanks, enderwiggin7!