I recently saw videos of Arthur Benjaman (the "Mathemagician") and saw him calculate day of the week in 3 seconds given the date and month. I checked out Zeller's congruence and then found an algorithm which isextremely simple.
Excellent. The formula in the site you have suggested is excellent, i have also tied to calculate some days of the weak and got succeed by the formula.
Thank for sharing. Now i can also calculate only in 3 minutes.