I used to make mud pies and mud cubes and other mud things with Shelby, who was my neighbor (to the right, or south) at the time.
I was thrilled that she had a huge play structure in a sandbox. I liked mine, but it was smaller and set on the grass. It was also older, and seemed to house a lot of insects.
The swings were meant for swinging and singing, for participating in how-high-can-you-get contests, and occasionally for reciting Disney movies. We twisted the chains around so much that their blue plastic covers ripped open, and we had to be careful not to get our fingers pinched in the links. Once when I was swinging high on the middle swing, the right chain snapped. I fell backward. That didn't do much damage, but it scared the heck out of me.
The vast expanse of sand was for burying things at first. My other neighbors' cat (to the left side) found a similar use for it, and eventually enough hard, old poop accumulated in the sand that we stopped digging.
We used the slide for everything but its intended purpose-- sat under it, buried things under it, dropped a variety of things down it, and so on. It was often coated in rainwater.
The "fort" part was a great place to sit and feel exclusive. It was especially convenient for secret snacks, such as raspberries that grew on the fence behind the sandbox. Technically the bush belonged to the other neighbors (to the back). We felt justified in eating its fruit, though, when we were told we couldn't have cookies because dinner was approaching.
I once told Emily, Shelby's little sister, that we wouldn't let Shelby "ruin our day" (she was being grumpy). She overheard me and I felt kind of bad, went inside later and told my mother, who told me I could have shown more benevolence. I felt even worse then, and I think I tried to make it up to her in kind gestures, but I never apologized.
We used to play tag a lot. Hide-and-go-seek was also really fun because there were so many places to hide: all around their big house, and behind trees, and around the shed, even inside it. We rode bikes and in the summer we watched for the boys across the road, when they stayed with their grandparents. The younger one, Duke, cried frequently. His grandma yelled at him even more frequently. I didn't respect her much, although I didn't show it.
Shelby's dad would stand outside after work and smoke. I remember his moustache and his voice. Kind of gruff, but not especially deep or scary. He was a nice guy, as far as I could tell; and I liked Denise, Shelby's mom, although she was rather tall and intimidating. When they divorced, I felt miserable for their kids. The dad moved out, and the others moved away a year or two afterward.