What a wonderful idea. You can now enable a feature in Google Mail (Gmail) that autoactivates late on weekend nights to stop you sending drunken emails – basically, it asks you to solve a few math questions before allowing you to send the email. If you can’t solve the problems, it won’t send the email.
http://gmailblog.blogspot.com/2008/10/new-in-labs-stop-sending-mail-you-later.html