"Cats and idiots like high places."... and one of my cats is an idiot, so he absolutely loves walking on top of curtain rods or trying to find a way up into the rafters if he could...
I got them one of those cat towers that I could just put up against the window so the huntress (younger sister) of the two could watch birds and growl at them, while the (older brother) height-loving idiot could just nap on the taller tower and feel tall. They're the only cats I've ever had that actually loves those cat towers.