If you asked most people to name the drink Canada is most famous for they'd probably cite either whiskey or beer.
They would probably need a lot of prodding if you wanted to elicit wine as an answer. But, given the enormous French heritage that is part of Canada, it is really no surprise that it has a very successful and thriving wine market and some wonderful wineries. In size terms, it doesn't match counterparts south of the border in the USA, and is dwarfed by the likes of California, but is large nevertheless.
As for style, it is very mixed, as you would expect from a country that has more than a thousand miles of land separating its two furthermost wineries. Ontario has the largest number of wineries, most of which work with Riesling, a rather interesting variety named Vidal (which is a cross between Ugni Blanc and Seyval Blanc), alongside the likes of Cabernet Sauvignon, Chardonnay and even a smattering of Cabernet Franc. There is also some very good Pinot Noir, as you would expect given the rather cool climate in the north of the country. However, its most famous export is probably its icewine. That is a wine made from grapes that have frozen on the vine during the winter months. The amount of juice extracted from these grapes is absolutely tiny, but extremely concentrated and sweet - as is the wine that results. It's highly prized and-you guessed it-highly priced, too.
Major white grape varieties: Chardonnay, Vidal, Riesling.
Major red grape varieties: Pinot Noir, Cabernet Sauvignon.
Key areas to watch: Niagara Peninsula (Ontario), Finger Lakes (Atlantic Northeast), Okanagan Valley (British Columbia).
Names to look out for: Burrowing Owl, Cave Spring, Château des Charmes, Henry of Pelham, Inniskillin, Mission Hill, Sumac Ridge, Tinhorn Creek.