Is it possible to complete a Master's degree while working full-time? Generally

There's a question which asks is it possible to get a PhD while working full time? The responses to this were essentially "yes but say goodbye to anything except school and work" or "only if you're a prodigy".

My first question then: can I complete a Master's degree while working without killing my social life? Browsing the course names gives me the impression that at least 10% will be review from my undergraduate degree.

Specifically

I'm interested in deepening my knowledge in my area (software/computer science) and am in NYC, where Columbia U would be a great option for this. I have completed an undergraduate degree and since a PhD seems like a stretch, I am considering a Master's degree.

My job has a 40 hour work-week but has flexibility with timing.
A lot of people in the US do this, actually. Some places have enough evening classes at the MS/MA level that it may not disrupt normal work hours. But it takes a lot out of the rest of your life, of course. 

It is easier in a field in which you can complete the degree without research, say by coursework and/or creative writing. 

But if you can afford to spend three hours a night in class for a couple of nights a week and also do the required other work then it can happen on a reasonable time scale. And NYC has a lot of options.