I am walking west between 18th and 19th on street passing Interior Bldg. I am on south side. An auto, headed north on 19th pulls up to curb directly ahead of me and 3 boys and 3 girls get out. They are laughing and shouting -- a typical high school crowd. I turn to left around an abnormally short block and find myself on a tennis court. I am in the way of the players and drop flat on ground in an endeavor to keep out of the way. One of the players knocks 2 balls (in succession) far out of the court. Next I am examining one of the rackets. It seems to me to be altogether too heavy. The strings, at least toward handle, are very wide. I ask, very politely, where the stringing was done.