Check out Somethingawful for some super-creative Photoshopped offensive board games.
WARNING - Above Link is super offensive.
Deal or No Deal game: Hooker Edition:
Pro-Life Operation board game:
Racist Board Games
First, some history, there were real racist board games, such as this real racist game from the 1930's called "Darkies in the Melon Patch":
There are also parody racist board games, offensive characatures of Black people, like Monopoly for Black People: