sanity check for http://en.wikipedia.org/wiki/St._Petersburg_paradox

gistfile1.py

from random import random

value = 0
acc = 0

payout = 2

for n in xrange(1, 1000001):
    for x in xrange(10000000):
        if random() <= .5:
            value += payout
            payout = 2
            break
        else:
            payout *= 2

    acc *= n-1
    acc += float(value)
    acc /= n

print acc/1000000