This is a description of each of the four houses (Gryffindor, Hufflepuff, Ravenclaw, and Slytherin). I used my knowledge of the books, as well as Pottermore, to create the posters. It showcases the strength of each house, as well as lists its potential weaknesses, so that students don't feel one house is superior to the others. It paints each house in an equal light.
I posted the house descriptions on a long bulletin board, and then had the students take sorting quizzes. I asked them to bring me a picture, and we hung their picture under the description of their house.