If I may suggest ...I will make sure to put i next to that big plate of rare roast beast!!!
You should take the high road and not drop down to their level of open antagonism.
Further, you could take some steps to melt their brains a wee little bit. Poke around the web and Google +locavore +your city's name -- put together a meal or two of local food. If you're going to serve that roast beast, find a critter that was pastured and /not/ feed lot raised. Vegans, FWIW, frequently succumb to tropical fruits come winter because a diet of cabbage, onions, potatoes, carrots and dry beans, while sustaining, gets a bit bland. And potentially smelly. But that all local meal ...
Many areas have an electricy provider like Bullfrog in Canada that sources electricity from sustainable sources. I'm not sure what the ones in the States are like, but we got stickers and such when we signed up with Bullfrog. A gesture like that is probably not likely to be missed.
Just a thought or two.