I took a sociology class once where we discussed the impact the Internet has on the social ritual of dating. Did you know there's a dating site out there for virtually everyone? Here's a few of the bizarre, random, and niche ones I've come across.

Pierced Passions - Are you a big fan of body piercings? A dating site specifically for singles with piercings.
No Longer Lonely - Do you hear voices in your head? Do you suffer from manic depression? Looking for someone equally as unstable as yourself? Then this dating site for the mentally ill is just for you.
420 Dating - I'll give you one guess what singles this site caters to.
Ashley Madison - This leaves me speechless. This takes the work out of having an extra-marital affair! Sign up and meet others you can cheat on your spouse with!
Veggie Lovers - This is a great site that connects vegetarians and like minded people with one another.
Sunshine Dates - A herpes dating site dedicated to those living with herpes. It gives them an opportunity to connect with others who can empathize and find support.