Pi is an incredibly useful number and not just for mathematicians, but for us overclockers too. The fact that Pi is a precise number that can be checked for accuracy means that programs which use an algorithm to calculate it can be used to check your CPU is operating properly (and therefore if that overclock is stable). Calculating Pi to huge numbers of decimal places has long been a popular pursuit and the record number was broken recently, using a desktop computer no less. Computer scientist Fabrice Bellard ran a program to calcuate Pi for 131 days in order to achieve the total of 2.7 trillion digits (the previous record was 2.6 trillion). He plans to release a version of the program used to make the calculation and carry on adding further billions of digits to his total.