Personally I've never even thought about Pi since I left school, but many people need need to calculate it on a regular basis. If you're looking for an easier way of doing this then give iPi a try.
iPi is a free and simple application for calculating Pi. It uses the function: 4 (1-1/3 1/5-1/7 ... 1 / (2n-1) -1 / (2n 1)) to calculate the value and can be set in motion simply by pressing the 'Calculate' button in the single-window interface.
Once you've hit the button, iPi will start processing the calculation, and you can speed up or slow down the amount of processing power given to the app using the handy slider. Alternatively, just check the 'Fastest performance' button for optimal performance.
In terms of its functionality, that's about it really. There's no flashy interface and the only other options available to you in iPi are the ability to start over the calculation or save the result.
If you're looking for a simple way of calculating Pi, iPi represents a no-nonsense solution.