Just read volume 4 of TAoCP when it appears in print :-). Actually, if your game is not about real money, this problem might be more of an academic curiosity,

Just read volume 4 of TAoCP when it appears in print :-). Actually, if your game is not about real money, this problem might be more of an academic curiosity, but there are some algorithms with very long periods, start at one of these pages to look for an algorithm with weaknesses that you can live with: - http://en.wikipedia.org/wiki/Mersenne_twister http://en.wikipedia.org/wiki/Mersenne_twister - http://en.wikipedia.org/wiki/Blum_Blum_Shub http://en.wikipedia.org/wiki/Blum_Blum_Shub - http://en.wikipedia.org/wiki/Pseudorandom_number_generator http://en.wikipedia.org/wiki/Pseudorandom_number_generator