In many Japanese homes, you are expected to change into a special pair of slippers when going to the bathroom. You have to rember to take them off and put your ordinary slippers on when you come out (or you will end up feeling very silly!). The idea is to keep damp from the bathroom from spreading in the house (quite sensible).
My host family do not have toliet slippers, but the church building in which I am sleeping does.
Last week, I decided to buy some toliet slippers to take home with me. When I get home, I am going to put them in my bathroom and freak out my parents.