For the sneakier amongst you, take a look at this site.
This viral-oriented site allows you to send an email to a friend that helps them calculate their love for one of their "crushes". The sneaky bit, is that the site takes your information and emails it back to the friend who recommended the site.
Sounds good at first instance, but it has caused quite a stir at my workplace. If you like a little chaos, feel free to recommend to someone at yours!