When I am tired, puns come out of my mouth naturally. I don't know if it's a disease, but I can't help it. Fortunately, I only utter them with close relatives. I will make an exception here.

Here are a few selected ones I can remember (as I make them when I am tired, I tend not to remember them well).

Asking my wife : "Could you give me the digital turtles ?"
- my wife : "..."
- (seeing that she doesn't understand) : "deji-kame" is short for "dejitaru kamera" isn't it. So in English, "digital turtles". One turtle is "kame" in Japanese. The plural is "kamera".

Today while going to the Ghibli Museum (which I do not recommend, btw) : "Mitaka ka Kichijouji eki, dochi ga ii no kashira ?" (I wonder which is better of Mitaka or Kichijouji station). The museum is located in the Inokashira Park, between these two stations...

Watching an anime on TV tonight, there was a doll of a mermaid, so I said : "kore wa ningyo no ningyo desu ka ?" (Is that a mermaid doll ?). The words for "mermaid" and "doll" are homonynous in Japanese.