Why does my cat do this?

She is 6 months old and enjoys being at the highest point possible in every room that she is in. I have vaulted ceilings in my bedroom with a window in the uppermost corner. She enjoys climbing the drapes tightrope walking the vertical blinds to get into that window which is very high. Then while we are sleeping she will leap from that spot into the middle of the bed, even if we are in it. I have had her land in the middle of my back, my stomach and my balls. Can anyone tell me why she enjoys doing this?