The Applied Sensors Kit teaches you about interfacing the world to microcontrollers.
This board is a great starting platform for learning how to take advantage of the Propeller.
The Propeller Proto Board Accessory Kit includes all the parts necessary to connect VGA, keyboard, mouse and servos to the Propeller Proto Board.
The PropSTICK is USB device which lets you access all the Propeller's pins on a 0.1" format.
The Parallax PS/2 to Breadboard Adapter makes it convenient to connect a PS/2 mouse or keyboard to breadboards, protoboards and perfboards with 1/10-inch hole spacing.