In James M's post about WFRP he mentions in the passing the ridiculous puns, especially in German.
Years ago on the WFRP mailing list (such a thing may still exist for all I know), Graeme Davis made an appearance and expressed amazement at how few of these puns and in-jokes had actually been noticed by WFRP players. Even then, mentioning my favourite (the nobleman Baron von Saponatheim mentioned in passing upon an advertising flyer in the Enemy Within) had people flabbergastedly remarking "I never noticed that one!" (You have to read it out loud or it doesn't work).
Anyway two of my faves from Graeme.
Middenheim is a pun that should be glaringly obvious but nobody ever seemed to notice, myself included. In castle architecture a midden is a simple piece of mediaeval sanitation - a vertical drop down into a cess pool. And Middenheim the city is a city perched upon a vertically-sided round spire of rock which is entirely riddled through with sewers which disgorge at ground level. The city is a mediaeval toilet. The clue is in the name.
Also, and this was one that Graeme didn't realise wasn't common currency outside of Nottingham - the whole Old Slann background had it's origin in one in-joke. You might be familiar with the pseudo-science works of Erich von Daniken, especially Chariots of the Gods a seminal work in the field of ancient astronaut theory. Personally I love all this stuff. Total shite but I can't resist any crap like this. I used to routinely find his books in second-hand bookshops filed under "Science Fiction" although TBH, the "Science" part is being somewhat kind.
In a discussion about von Daniken's books, somebody at GW jokely turned the title into "Chariots of the Frogs" suggesting that the ancient spacecraft had disgorged bactrian astronauts onto ancient pre-Columbus Meso-America. (I suspect this was Richard Halliwell as Lustria sprang from his home campaign).
Obviously a Eureka! moment - the entire Warhammer and Warhammer 40,000 backstory sprang into life from this silly play on words.