Dodgeball
The game was so fun. What's better than being allowed to bean kids you dislike with a hard, textured ball? Aside from that, I was actually good at it, unlike most other games.

Two/Four square
It was such a basic game with so many arbitrary rules. Sometimes there would be no "corner bouncies", other times no "high bouncies"... sometimes both and some other rules I can't even remember anymore. It was fun because turns were based on who won. If you won the match, you stayed in and the losers got out and back in line... and I hardly ever lost.

The Lady in the Sewage Drain
This sounds like a hokey horror book, but it was the pastime for a good portion of my 3rd grade. My friends and I came across this sewage drain in the playground and it just looked so creepy. You could see straight down to the bottom through the widely-spaced grate. There was also some "mysterious pipe" (drainage pipe) in which we decided some creepy Lady must live. The fun part was making up stories: why she was down there, what she would do, etc. and acting like she was really there and would come out and grab us with her thin fingers at any moment.