So what is the joke with the ghost in the hotel in goodbye deponia?

As far as I remember there never was a ghost - only a peeing Tom. Which joke exactly do you mean?

"Peeing" Tom? Heh. Heheh.

That of course was not what I wanted to type ;)

When the "ghost" is scared because of the scream from the bald guy, you only see a sheet on the floor, and Rufus says: " there is a good joke here, but it got lost in translation"

So i think is a German joke, but it will loose its meaning if they translate it to English.

I just watched a german playthrough to remember and yeah, the joke is lost in translation which means it is not translateable. I try to explain it.

When Rufus looks at the sheet on the floor in German he says

"Ich verstehe, es ist ein Spannbettlaken." which would translate to "I understand, it is a fitted sheet".

The German word "Spannbettlaken" means a fitted sheet. The German word for a peeping Tom however is "Spanner". The sheet from the "Spanner" is a "Spannbettlaken" means that it belongs to the "Spanner" and it is a fitted sheet. The joke is meant in the way that Rufus just says what a kind of sheet it is and at the same time tells what kind of person the sheet used. He never uses the word "Spanner" (or peeping Tom) and still says what the player already thought.

I have no idea how they could save that joke so they decided to just let it got lost in translation.

Ok, thanks for explaining the German joke.

When you try to use everything with the nut in the hotel restaurant, you'll get a bunch of yo mama jokes in German. The logic behind that is the double meaning of "Mutter" which is either "mother" or "nut".
They didn't even try to let him say different jokes in the English translation.