What's a Calorie?

I stumbled across this website today, thanks to http://mybeerbuzz.com/, http://www.beer100.com/beercalories.htm. It gives the calorie information of many beers. Very cool.

Best reply I have ever heard about calories. One lady asked the bartender how many calories were in a certain beer. The bartender pointed out that, since there wasn't any calorie information listed on the lable, the beer had zero. I think the lady actually believed the bartender, because she proceeded to order the beer a couple times that night.