Share a What?

I'm continually fascinated by the peculiarities of British vs. American vocabulary -- or as someone put it, the fact that we are 'divided by a common language.'
My most recent discovery came from an American friend who had just recently returned from a trip to the UK. He heard a fine, upstanding Christian woman state that, after church on Sundays, they like to invite a few people home with them to 'share a joint.'
Knowing that certain standards can vary from one culture to another regarding things such as alcohol and tobacco, for example, my friend didn't dare react too strongly -- but as open-minded as he was, he had a hard time picturing this lady passing around a reefer after church.
It turns out, as you British readers must be smiling right now, that a "joint" refers to a cut of meat, such as a shoulder of ham or perhaps a leg of lamb.


I'd love to hear your stories about linguistic laughs within the English language -- please share them in the comment section!