I call it "street baseball." All you need is a bat, a ball, a catcher's glove, and maybe a few road barricades. (That last item is a lot easier to obtain than you might think; summer is the season of sidewalk reconstruction and they just leave them in the middle of the sidewalk all thieving-night long!)
To play, gather a few friends and divide evenly into two teams. Each team must have a really cool name like "Collective Jyrk" or "Charm Bracelet" or "The Art Mafia Fags."
Next, choose a busy street and quickly set up the barricades. Do so with authority, and don't take any backtalk from the SUV drivers! The game is just pitching and slugging. Each player gets three swings. Unlike "real" baseball, teams simply alternate players at bat. There is no score. The game ends when someone breaks a window and the players scatter in every direction.
And, who knows? If the game really catches on, maybe city hall will see that there isn't really any need to waste money building their silly major league stadium. MB