I'm 45, and I've been gaming on consoles since the Magnavox Odyssey. Many of the games I've played over the years represent a huge investment of time and a huge return of pleasure in playing, so I keep them. I keep them on shelves in my office, I keep them in bins in my basement. I don't get rid of them for the same reason I don't toss my old vinyl albums or CDs — in many cases, there's a real emotional attachment.
But this isn't about my hoarding tendencies. It's a good thing I've kept those old games around, because now I can play them again on my Mac. A powerful application provides the framework to do it easily, and it's absolutely free. It's called OpenEmu, and here's how to use it.