He's 2.5 right? For my kids going on the slide at a busy playground was the single best lesson in turn taking, playing fair & following rules. They have to learn that you go up the ladder and down the slide, get off and out of the way fast, don't climb back up the slide (when taking turns with lots of kids), no wasting time at the top, no pushing, etc. There are quite a few rules, but it all moves fast so it's not boring waiting your turn and you don't need to know or make friends with the other kids to learn the lesson.
