A fun harmless means of getting even is if you know the e-mail address of your target is to register them for every newsletter/pic/joke/etc. of the day you come across. While they will be able to easily unsubscribe, the fact they sell mailing lists will keep the victim innundated with junk e-mail for weeks. (things get real interest if you have a work address and sign them up for daily e-mailings of an adult nature)
Not So Spiritual Words 