Gintoki discovers that fans (senpuki) are considered obsolete technology in the alien-influenced Edo. He eventually finds a suspicious recycle shop run by a woman who misinterprets his request.
A pun-based misunderstanding occurs: Gintoki wants a "senpuki" (electric fan), but the woman thinks he is asking for the "senpuki" (a counterfeit-gold machine) created by her inventor father. Gintama Episode 21
The Yorozuya office is unbearable due to a massive heatwave. After Gintoki and Kagura fight over their only electric fan and break it, Gintoki heads out to buy a replacement. Gintama Episode 21