The Illuminati would be one of the biggest conspiracy theories in my opinion. I think the group exists. "New Order of the Ages" just seems like a possible alluding factor to a "New World Order".

Lizard people rule the world.

That the government purposely put fluoride in our drinking water to calcify our pineal gland so that our brains don't process to their full potential and we are easier to manipulate and control. They say it's good for your teeth, but is it really? Fluoride is highly toxic...

Television is brainwashing us. There are subliminal messages in all adverts designed to keep the population stupid, so that they do not realise how truly unfair it is that their lives are being ruled by governments who are just making things worse for them. If people all stopped watching television and going on the internet for a year, they would all snap out of it, live a happy life in a Utopian world. The government just keeps us stupid because that way we're easier to handle. Which is why they make Jersey Shore, Big Brother and other inanely stupid programs..!

IT'S TRUE PEOPLE!

Haha heres my favorite. The cartoon conspiracy theories are hilarious or creepy..

http://curiousworld.hubpages.com/hub/Cartoon-Conspiracy-Theories