Mizu-kake Matsuri is basically a mikoshi parade, an only-in-Japan festival, specific to the Shinto religion... But it is more to it than just the parade: during the festival the mikoshi bearers are constantly splashed with water by spectators "armed" with buckets or even with hoses... A great source of fun and play, but there also a spiritual meaning: at the origins, this was a way to express wishes for one's good health...
EXIF info:
Nikon D90
Lens: VR 18-55mm F/3.5-5.6G
Focal Length: 24mm
Aperture: F/5.6
Shutter Speed: 1/320s
ISO Sensitivity: ISO 200