Uses Zeller's congruence (found here: http://en.wikipedia.org/wiki/Zeller's_congruence) to figure out which day of the week that the date is! --- Uses python2.7!

DayOfTheWeek.py

'''
Created on Apr 11, 2013

@author: andrewkerr
'''
import math

input = raw_input("Enter your birthdate in a YYYY-MM-DD format:")

year = int(input[0:4])
month = int(input[5:7])
day = int(input[8:10])

# Makes check for Jan/Feb
if month is 01 or month is 02:
    month = month + 12
    year = year - 1
    
century = year/100
centuryYear = year % 100.0

dayOfTheWeekNum = (day + math.floor((13 * (month + 1)) / 5) + centuryYear + math.floor(centuryYear / 4) + math.floor(century / 4) - (2 * century)) % 7

days = {1: "Sunday",
        2: "Monday",
        3: "Tuesday",
        4: "Wednesday",
        5: "Thursday",
        6: "Friday",
        0: "Saturday",
        }

print "You were born on " + input + " which is a: " + str(days[dayOfTheWeekNum])