gistfile1.m

// totally works!
  [UIView animateWithDuration:0.5
                        delay:0
       usingSpringWithDamping:.5
        initialSpringVelocity:1
                      options:0
                   animations:^{
    CGRect bounds = self.scrollview.bounds;
    bounds.origin = CGPointZero;
    self.scrollview.bounds = bounds;
  } completion:^(BOOL finished) {
    NSLog(@"Bounds: %@", NSStringFromCGRect(self.scrollview.bounds));
    NSLog(@"offset: %@", NSStringFromCGPoint(self.scrollview.contentOffset));
  }];