Have you ever sent a mail, under the influence of alcohol, that you regretted the next day? Now you can avoid those with Gmail.
Gmail have a feature that lets you pick days and time when the sending of mail has a small lock. But don’t worry if you absolutely must send a mail during the chosen time frame, you can unlock by solving a few simple maths problems, within a certain time.
The default times are Friday and Saturday between 10 pm and 4 am, but can easily be changed. You even get to chose a level of difficulty of the maths problems 
There’s 5 levels. Unfortunately you can’t chose different time frames for different days.
The function is found under the tab Labs, and is called Gmail Goggles
i read about this article somewhere else….any ways this app is not for me for the reason i am not a drunkard