Sieve (quickly thrown together)

sieve.py

 6 import math
  7
  8 def sieve(n):
  9     a = range(n+1)
 10     a[1] = 0
 11     index = 0
 12     while index < len(a):
 13         if a[index] != 0:
 14             increment = a[index]
 15             for i in xrange(2*increment, len(a), increment):
 16                 a[i] = 0
 17         index += 1
 18     return a
 19
 20
 21 print sum(sieve(2000000))
~