Here's something for the Geeky Pinky. Texas Instruments has introduced a graphing calculator for you.
It has an alphanumeric screen and does calculus, logarithm, trigonometry, matrix, forecasting, and polynomial functions, among others. It has a 24kb memory, plus flash and uses 4 AAA batteries.
If you are interested, shop around--I've seen pricing as low as $99.
Have at it!