I remember way back then when we used to sweep the classroom floor and sprinkle the floor prior to it so the dust would not fly.
In Japan, people sprinkle water on streets and pavement to try and keep them cool on hot summer days.
contemporary (Heisei) version
Choose from domestic articles, such as buckets, pots, bottles, jars, etc
You may also use your hands or pour directly from watering cans or PET bottles.
[!] Wear a hat or a cap if available to protect you from the sun.
NOTICE: Watch out for cars. Do not bother passers-by.
The tradition got a twist with Uchimizzuko where 'maids' do the sprinkling.
Extreme Matsuri shares some details on the event including the Danny Choo video (of 2007 event) below.
Let's get cool for Tokyo Thursdays # 99
Previously on Tokyo Thursdays:
Night Lights Floats, Nebuta Matsuri or Tachi Neputa, Early August Festivals in Japan