the over the door cat climber.

An ad from Hammacher Schlemmer:

The Over The Door Cat Climber: This is the

out-of-the-way, door-hung apparatus that allows cats to exercise their feline propensity for climbing, stretching, pouncing, and lounging in an elevated position. Four fully carpeted 17" L x 8 1/2" W x 1" thick platforms that stimulate cats' natural curiosities attach to a wooden support pole covered with a sheath of sisal fiber that encourages scratching for healthy claw and muscle development.The platforms provide secure sleeping places for cats without taking up extra space. The pole has a bracket that attaches easily and securely to the top of doors (a spring-loaded bracket fits to the bottom of doors for easy installation), yet it is light enough to allow you to move it from door to door as you please, providing more interest for cats; doors can be closed while the climber is attached.

All I can picture is a cat sleeping on this thing, someone opening the door and the cat flying off.