Afternoon in Smithfield

I was thinking of taking my kids out for a fun afternoon now that the weather is getting nicer, and I realized that with our shorter commute times, we have a bit more free time on our hands compared to other towns. Since the average commute to work is only 23 minutes, I'm guessing many of us have some extra time to explore our local area. What's the best local spot to take kids on a free afternoon like today?