For accounting majors and other Excel wizards, a numeric keypad is indispensable. Unfortunately, the Apple Wireless Keyboard that comes with iMacs these days doesn't have such a keypad. Mobee has come to the rescue with Magic Numpad, a temporary adhesive film that attaches to the Magic Trackpad and converts it into an extended numpad, a numpad + trackpad, or a numpad with user customizable keys.
The Magic Numpad includes software that is Lion and Snow Leopard compatible and could be a useful alternative to spending $49 on the Apple's full-size wired keyboard. It won't have the exact same tactile feedback as the keyboard, but for some users it might be just what they're looking for. Combined with the TwelveSouth MagicWand, it will (sort of) convert a wireless keyboard and Magic Trackpad into a full-size wireless keyboard.