If you've reached the seventh floor corridor, then you have almost reached the Ravenclaw Common Room... assuming you know where it is.

At the top of a spiral staircase is a door without a doorknob or keyhole but a bronze knocker in the shape of an eagle. In order to enter the Ravenclaw common room, a person must answer a riddle asked by the eagle knocker; if they answer incorrectly, they must wait for someone else who gets it right. This might lead overconfident non-Ravenclaws to believe that they could break into the common room at any time, but then they would have over-exerted themselves climbing all the way up there only to be made to feel stupid by a simple door knocker.

If you're waiting on a friend, you can have a seat on the staircase leading up to the knob-less door and feel grateful that you don't have to walk all this way every day just to go to bed.