My favourites from the days when (alledgedly) I did that sort of thing...
Were the flllowing subject lines...
George Bush is dead
followed in the body by...
against you visiting this site
or
Got nude pics of your wife????
followed by
Want some?
One of the best responses membership wise was from an email that basically solicited people to send in videos pics etc of their wives and girlfriends.
We played up big time how we weren't one of those big corporate fake amateur sites and only accepted pictures from "Real" girl next door / housewives.
that we would buy there videos and pics etc....didn't spam the site...just had the url under the sig of the sender of the email.
People went out and checked it out and joined ;-))
sneaky huh?