Actually, we only have a couple that anyone even hears about.
The Green, NDP and Liberal parties are the left wing parties (in order from craziest to most moderate) and on the right we have the Bloc Quebecois (national party, but you can only vote for them in Quebec, and they are seperatist) We used to have the Progressive Conservatives, but they broke up and the Reform party took their place, and the Reform/Conservative party, a bunch of crazies like your Republicans. (Once again, ordered from the most central out to the crazies).
Now, only the Liberal and Conservative parties have ever been in power (well, the PC had power, and when they broke up, the Reform took their place and changed names to just the Conservative party). NDP is the next party likely to ever get in, if the rest of Canada smartens up, but I still think it's a long way off. And the green party, well, they're a bunch of pot smoking environmentalist hippies, lol.
In Canada, more often than not, we don't vote for a party, we vote against one we don't like, lol. And every now and again a party manages to get involved in some sort of scandal, and then they get voted out for a couple years until the other party fucks up.