So here in the US we have a bloody Mary drink which is pretty much a staple at most places serving brunch and booze. The Canadians have their own versions that are much more popular.
First they like their Cesars. This is what you'll see way more often than Mary's. The base alcohol in this one is vodka, but it is filled with Clamato. Clamato is tomato and clam broth together. They are surprisingly not too fishy and you'll find celery salt around the rim instead of regular salt.
The bloody Maria is pretty much our version of a bloody Mary just with tequila instead of vodka. These seemed pretty common too. Though I know of several places in the US who offer different varieties of booze in those as well. These seem to frequently have clam juice in them as well in Canada.
And if you're looking to be totally American, try yourself a red beer. That's a cheap, usually pale (think PBR, Coors) and tomato juice mixed.