I was amazed to see a full page ad in Newsweek for this product billed as a $1000 kit to "turn any vehicle into a hybrid".

http://www.preignitioncc.com/nw/index.htm

It appears to be a catalytic converter that is plumbed into the fresh air intake. The advertisement in the magazine and web site make some fantastic claims for mileage improvement. I especially like the video where a guy in a bad toupee runs a lawnmower engine on Pepsi and some other strange ingredients.