I believe that saying it's not what you do, it's how you do it. When you get 2 days with the person you love, how will you spend it?
I recommend adventure. My husband and I just got back from our 2-day stay in Montréal. It's just 4 hours north of our home in New York - I couldn't wait to whip out my passport for this one! Whirlwind getaways like this are so romantic, especially when you don't tell a soul you're going anywhere.