This isn't a language joke... But I thought it was pretty funny, although it's a bit racist. My aunt told me it.Two Japanese and two Korean people were at a train station. The two Japanese people each bought a ticket, but only one of the Koreans bought a ticket. The Japanese people thought, 'Hah! they're going to get caught!'
The four people got onto the train. When the ticket inspector came, the two Korean people went into the toilet. The two Japanese people gave their ticket to the inspector and watched what would happen to the Korean people.
When the inspector knocked on the toilet door, a hand came out, holding the ticket. The inspector took the ticket and walked away.
A few days later, the same four people were on the train again. The two Koreans again only bought one ticket, and the Japanese did the same.
When it was time for the ticket inspector to come by, the two Japanese stood up and quickly went into the toilet before the Koreans did. One of the Korean went to the toilet, knocked on the door, and said: "Ticket inspector, please hand over your ticket."
It's pretty obvious what happened next.The Korean took the ticket and sat down. When the ticket inspector came, the two Koreans presented their ticket to them. The inspector then went and knocked on the toilet door, but the Japanese didn't have any ticket to give to him.