p15: traversals through an array
p16: sum of digits in 2^1000
p17: number of letters in the 1..1000 written in words
p8: max prod of 5 consecutive digits in a 1000 digit block
p11: maximum product of 4 items in a straight line in a grid
Added comment
p13: sum up a list of long numbers
p19: Calculate how many months started on Sunday in the 20th century
p20: sum the digits in 100!
p18: Triangle path sum
Added solution for p67, the larger triangle
p63: find all n-digit powers of n
p48: sum of powers.  Ruby made this too easy.
p70: minimum totient(n) ratio that's an anagram of n
Quick readme of how I solved this one.
Added note about an alternate (less optimal) solution
p28: compute the sums of the diagonals of a number spiral
p30: numbers that equal sum of the 5th powers of their digits
p21: Amicable numbers
p22: sort and score a list of names