"Antonio Jorge Goncalves makes drawings of people sitting in subway trains in 10 cities around the world. He stays an average of three weeks in each city, making around 300 drawings which seek to cover different times of the day and the different lines in the subway system."
Not having heard of it, I popped over to the website - Subway Life - to have a look.
I haven't had a look at the other lines yet but thought the London ones were interesting:
My particular favourite is the one of the bloke below with hair, like chips or chips for hair.