There are many manga cafés or internet cafes in Japan and they are very popular.
Manga café is a café which has manga (comic) library and also an internet facilities. You can read your favorite comics as much as you like and you can also use an internet or watch TV or DVD in a private space. Some of the cafe also have some amusement facilities such as billiards, darts, table tennis, shower, sauna, massage chair and even tanning machine!! You can buy some foods if you are hungry and mostly they have free drink service.
Usually it charges per hour and you’ll pay when you go out.
It opens until morning so some people uses as a place to rest when they missed the last train as they are cheaper and convenient than the hotel.