The 50-50-90 rule: Anytime you have a 50-50 chance of getting something right, there's a 90% probability you'll get it wrong.
Question #2177 posted on 12/26/2003 midnight
Q:

To the hammer guy,
When the penny fell I believe it would turn vertically (so it's edge was leading) and therefore the maximum velocity thing would be higher than that of a sphere. Also, the guy who said it would hurt more because smaller area of contact was also right. I don't think it would kill you though.
Just guessing, of course.

-The Tall One