I got an email with this subject:

1000 men will get laid tonight - be one of them

OK, according to the the Census web page there are 6,302,680,242 people in the world. Half would be men, so that's 3,151,340,121 guys. Let's say only 1/4 of those are sexually active (seems very conservative!). That's about 787,835,030 guys and of those 1000 will get lucky tonight or 1 in 787,835. Which also means that on average guys are only getting lucky once every 2158 years. This seems a wee bit low to me.

Note to porn spammers: I'd say a very conservative estimate would be that the average guy is having sex at once a month or so, and so the email would be more accurate if the subject were:

26,261,167 men will get laid tonight - be one of them