This file runs in both Ruby and Python...I didn't realize they were quite so similar!

Euler5.py

#!/usr/bin/env python
#!/usr/bin/env ruby
# take your pick!

def gcd(a, b):
    # greatest common divisor...Euclidian algorithm
    while b != 0:
        tmp = b
        b = a % tmp
        a = tmp
    return a

def lcm(a, b):
    # least common multiple (via GCD)
    return (a * b) / gcd(a, b)

def lcm_arr(args):
    # least common multiple from a list
    if len(args) == 1:
        return args[0]
    else:
        return lcm(args[0], lcm_arr(args[1:]))

print lcm_arr(range(1,21))