Some embodiments are directed to an adjustable arm rest attachment mechanism that includes an outer bearing non-rotatably fixed to a seat and defining a first guide groove. An inner bearing is non-rotatably fixed to an arm rest, and defines a second guide groove. The inner bearing is rotatable relative to the outer bearing, and is disposed over the outer bearing. A pin extends through the second guide groove and into the first guide groove. The pin and the first and second guide grooves are configured such that, if the arm rest is rotated downward within an adjustment zone, then wall surfaces of the first guide groove selectively engage and disengage the pin, and simultaneously, wall surfaces of the second guide groove selectively engage and disengage the pin, thereby creating a varying frictional force capable of impeding further rotation of the arm rest.