A woman was standing at the ticket counter of the railroad platform and asked for a round-trip ticket. 

“To where?” asked the ticket agent. 

“To here, of course,” replied the woman.

What’s So Funny?

The ticket agent wanted to know where the woman was traveling to on the first half of her journey.  The woman said “here” because this was where she wanted to return at the end of the entire trip.

Vocabulary

round-trip ticket = going to another location and then returning to the starting point

one-way ticket = going somewhere and not returning