I highly recommend packing a lunch/dinner and heading over to Norton Art Gallery to check out the azaleas.
Yeah, it sounds cheesy, but they're gorgeous and it's an easy way to spend time with your favorite person without doing the same old dinner and movie shtick. Plus, they don't last long so it has that special, limited-engagement quality.
Bring your camera and if you're lucky you'll get some fun shots like this one from The Times' Greg Pearson. (If I were this kid's mom, I'd have this one blown up poster-size).