http://calcr.com/
Quote
Web site calcr offers users a very simple but useful online calculator.
As you perform your calculations, calcr dynamically creates a tape that tracks each calculation. Calcr can handle parenthetical expressions like (3+2)*5 and can also support several functions (e.g., abs, sin, cos, tan, asin, acos, etc.). In all, calcr is a quick, easy, and elegant online calculator.
Found on http://www.lifehacker.com/software/calculator/perform-calculations-online-with-calcr-164360.php
I like it - now I just have to remember another URL
