I've got one! How about Grond the battering ram used during the Siege of Gondor? Calculating the weight, angle, and velocity needed to break the Gate of Minas Tirith must have been a pain for those silly trolls.
How about the perfect angle at which to attach the stirrup to David Wenham's leg as not to break his ankle when Faramir was being dragged in though the Gates... in full armour... stuck full of arrows... *trails off into grumbling*
The trebuchet one was great, Sir Kohran.
