www.urbandictionary.com
I laughed pretty good at this one:
1. dutch hand grenade 71 up, 12 down 
In a similar mould to the dutch oven, but the air biscuit is caught in the hand, which is then used to transport the pungent aroma as close as possible to the victim's nostrils before it is opened.
What are some other good ones? I just noticed that you can now buy mugs/go-cups with definitions printed on them, so I'm looking for a good one to order.