Have a water balloon fight or snowball fight, depending on the season.

“Even though my friends and I had come there as a team and had planned to stick together, as soon as the snowball fight started, we all suddenly dispersed. Around me, I heard screams and people bursting into fits of laughter. I saw people sprinting across the Green, trying to avoid getting hit by their provoked rival. I saw people vigorously tackled onto the ground as they plummeted into the heap of snowfall below them. WOOSH. All of a sudden, a cold snowball hit my ear. "Who was that?" I yelled, laughing as I brushed off the snow from my cheek. I couldn't see people all too clearly because it was dark outside; however, I recognized the face of one of my friends. Forming a snowball in hand, I got up and chased her through the middle of the Green.”

“As we walked down the sidewalk and my son slipped his little mittened hand into my much larger gloved one, I was still working on that last problem on my desk. As we approached the park down the street from our home, I was thinking through my upcoming calendar of events. As our little guy took off running for the big snow-covered hill, I was stuck in the office, trying to pin down all the disparate, elusive threads of my day. It was a snowball, smacking solidly into the small of my back, that snapped my brain back into my body. My son is pretty coordinated - for a two-year-old - but the integrity and velocity of the snowball makes me suspect he wasn't the one who threw it. My wife, for the record, can neither confirm nor deny my theory. And as I scooped up a handful of snow, the choice was made.”