R.J. McNamara built this great Mindstorms bottle opener:

I decided to tackle building LEGO Mindstorms NXT Bottle Openers… The task turned out to be somewhat more difficult than I envisioned. The most difficult part by far was the Gripper Mechanisms, as they had to securely hold the Bottle and it’s cap in a manner that allowed them to be unscrewed…

A single NXT Brick controls the ‘Drink Bottle Opener’ Mechanism. It us 5x NXT Motors, 2x RCX Type Touch, plus 1x NXT Touch Sensor to Stop and Start the Robot. To control the two extra NXT motor, I have used a Mindsensors MotorMux which requires an additional 9 Volt power Supply.

I love how the video shows off whatever sub-assembly is currently in operation. [via the NXT Step]