Shake Gesture

If you are planning to use the shake gesture to trigger an event add the following code to your UIViewController

-(BOOL)canBecomeFirstResponder {

return YES;

}

-(void)viewDidAppear:(BOOL)animated {

[self becomeFirstResponder];

}

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {

if (event.type == UIEventSubtypeMotionShake) {

// add the todo code here

}

}

From: http://iphone.detailsfinder.com/en/2010/detecter-un-shake/

I would also recommend reading

http://developer.apple.com/iphone/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/EventHandling/EventHandling.html#//apple_ref/doc/uid/TP40007072-CH9