Guild Wars 2 Weapon Preview

If you're curious about anything weapon-related in Guild Wars 2 - including sets, skills, and customization - you should check out this two-page image-laden weapon preview over at Ten Ton Hammer.
Certain objects in the world can be picked up and carried by the player to be used as a weapon. To pick an object up, approach it and press the [F] key when in range. Upon doing so, your skill bar will automatically swap in any new skills associated with holding that object.

In the example shown above, the player had picked up a Jar of Bees which can then be thrown at enemies to do AoE damage. Once the jar is thrown, the skillbar will automatically swap back to the normal core skills for your equipped weapon set.

Certain stationary objects can also be used in a similar manner, such as the cannons and mortars used in the dynamic event fight against The Shatterer as seen below. In this example, should the flow of battle turn in the favor of The Shatterer's minions, it's possible that they could push the fight back far enough to destroy the cannons and mortars. Should this happen, it begins another event chain where players are tasked with escorting a supply train into the area. Doing so will give them the ability to fix the cannons allowing them to be used again during the event.