Washtub Throw

In Hot Springs Episodes, the female characters will catch the male characters walking in, spying on them, etc. One of the first thing the former will do is throw wooden buckets, wash tubs, or any bathing tool, at them, given those are pretty common items in a hot spring.

Compare Bath Kick and Drop the Washtub.

Anime and Manga

 * Used frequently in Ranma One Half: the resident Dirty Old Man Happosai has his own variation called hermit crab technique in which he throws several buckets into the air and uses his small size and speed to Flash Step between them and attack from inside them as they fly past his opponent.
 * Kagato was on the receiving end of this in the Tenchi Muyo! Original Video Animation.
 * Occurs in the Rurouni Kenshin anime when Kenshin inadvertently blunders into the ladies side when he's a bit too excited to share an Eureka Moment.
 * Zoe Ornimoto from Digimon Frontier did it

Video Games

 * Persona 4: when the male characters stumble upon the female characters in the hot springs, the latter continuously throw a ridiculously amount of wooden buckets at the former. No amount of Courage the main character can have to be able to "hold the line".

Web Comics

 * In Megatokyo in a public bath, Piro hears Miho and Yuki screaming and rushes to their aid. Miho (who previously tolerated his presence well) stops him in his tracks with a thrown washtub, apparently afraid of Yuki's reaction to Piro seeing her.