Bad gaming pun of the week: An inn, whose sign consists of a two stags rearing up underneath a star, specializing in pastries and hot drinks especially of the coffee variety...
I wonder how long I could keep such a thing going before my DM noticed. Perhaps when I open a second inn/coffee shop directly across the street from the first? 
You can have hours of fun with this, I usually slip these in when I am the GM. If one of my puns does not elicit a groan or two, I know that I am not doing good enough job as a GM.
A friend recently managed to get the following in his campaign (as a player) a black carriage with red lines on it, a character who smokes cigars a lot and comes up with the plans, plus a character with a fear of frying (an intentional spelling mistake, the character has a phobia of any fried food that has entirely baffled the GM).
One of my player's PC (im the DM) was once a bodyguard for a Lich-in-the-making who was living in Sigil. He wheeled around an I.V. stand with several bags of alchemical mixtures in them. This Necromancer almost-Lich had a zombification business, and it just so happened that his tower on his homeworld had been attacked (the reason he was in Sigil and hiring bodyguards, y'see, lots of enemies at home) by a band of adventurers with vorpal swords. So, of course he was having a half-off zombie sale....
"I'm not only the owner, I'm a client."
"We start with the freshest corpses." [rejects the headless one ... goes to the drowned one and pushes on the chest, gives thumbs up]
"We add our secret blend of 47 potions and spices."[strange, green glowing I.V. bags]
"We have everything from your economy models..." [regular zombies] "..and pre-owned..." [hacked-up zombies and skeletons] "...to luxury models..." [female vampire in S&M leather and whip] "...and SUVs." [undead ogres and giants]
The "luxury models" bit completely cracks me up. The others are great puns, but the image of a Lich selling the services of a vampire dominatrix in a TV commercial is just too fun for words.
A goblin chieftain once offered a female goblin guiding ranger to players. He said she was really really good. If someone wouldn't believe that, he could try her in the back tent 
In a Shadowrun game I've played, the PCs favorite hangout was a bar decorated in Early Soviet Russia style. It was owned by a guy named Karl, and he bought it from a guy named Mark. As a result, it was Karl's Mark's Bar.