Google has a feature that requires you to answer some simple math questions before it will send any email that you compose (typically on a Friday or Saturday night). In theory, if your sober enough to answer the math questions you're less likely to send an embarassing email that you'd later regret.
Sadly, my math skills are usually quite good when I've been drinking. At the point that they decline, I've usually lost the ability to type too. (grin)