Please don't answer this unless you actually know. Post your experience/credentials.
1. What could make a skunk spray, besides dogs or people? We've been here for 10 years and never had a problem. Suddenly, there was spray twice last week, so bad we were gagging insides the house with all the windows shut. We don't have a dog and my neighbors' dogs all stay on their leashes. I've never seen any critters in my yard except the skunks, woodchucks and turkeys, and of course the small birds. I've never seen a raccoon or a deer here. We're several blocks from any woods. I'm sure we have small rodents because I keep a little patch of habitat and some of the neighborhood cats hunt in it sometimes, but in my experience, cats and skunks get along well. Would a skunk have sprayed a cat or another skunk?
2. I saw a huge one in my garage tonight. It's a wooden garage with a concrete floor and the overhead door is broken right now, so it's open. Is there a way to tell if it's hunting or nesting, without getting into trouble? If it's nesting, can I use the garage to park my car? I know I can drive the skunk out with ammonia-soaked rags or something, but I don't want to unless I can't park the car in there. In Maine, leaving the car outside in winter is a lot of work. Sometimes it can kill the battery, and shoveling it out of drifts takes forever.