A PC in my current game is a caster based around intimidate and fear. After a particularly long dungeon that left his spells drained, he took to using a wine bottle they had found, breaking it, and wielding as an improvised weapon just to demoralize enemies and use his draconic presence. It actually worked pretty well.
Back when I had my Warblade samurai character, I made sure to take Insightful Strike and looked forward to doing things like using a teacup from a tea ceremony as a weapon, but the chance never came.
In a non-D&D game that the game master had made up the rules for, we all played monsters working together to exterminate humanity. One of the players had a "sentient catapult" who regularly loaded up with corpses, trees, cows, etc... to use as ammo for launch. He also liked to launch the melee people into close combat, a sort of "assisted charge / dive attack." My character was a gargoyle and allowed him to use the extremely hard (and thus damaging) stone form he took during the day as ammo, as long as he was careful to not fling him high or far enough to risk breaking him.