What do you call a retard in a sauna? A steamed vegetable.
I don't think that's appropriate. Why would you joke about disabled people like that?
I heard it on TV and I thought it was funny. There are jokes about different groups of people. There is nothing wrong with that.
Just because you heard it on TV doesn't make it right to repeat it. Brain injuries can happen to anyone at anytime and it's not right to joke about people who are mentally challenged. It's important for you to consider how you would feel if you or someone you care about were to suffer from a mental disability.
I don't have much sympathy for retards. Who cares.
What if your mother was mentally challenged. Would you find it acceptable to tell that joke to her? Mentally challenged people already struggle a lot, and jokes like that make it even more difficult for them to be accepted.