Before you just walk into a coffee shop and plug in your microphone, you may want to check that you're allowed to do so. I don't think this is a large problem in most cases, but you never know when you're going to stumble across some coffe-shop-owning-curmudgeon who will tell you to shut it down.
In Canada, stores are still considered private property and owners can exercise almost as much control over the activities therein than they can in a private house. Yes, there are rules about service, discrimination, parking space, bathrooms, and fire exits, but few limits on the banning of activities within the building.
Concerts, presentations, and expositions are much more likely to have restrictions on what can be recorded and who can do so. Many podcasters these days are having a lot of luck getting media passes to events, though, so if you're looking to record such an event, contact the press people and see if they'll set you up.