The Mersenne twister is a fast, efficient pseudo-random number generator with a very long period. It is unsuitable for cryptographic uses, but it is more than adequate for computer games. Due to its speedy and effective generation of pseudo-random numbers, a few languages (e.g. FreePascal and Python) have already begun using the Mersenne twister as its default algorithm for its own RNG.
It is not necessary to understand how the Mersenne twister works in order to use it.
The original C source for the MT: MT Source
The official webpage of the MT: Mersenne Twister Homepage
C++ optimized port of MT: C++ Mersenne Twister
A description of the algorithm on Wikipedia: