Someone on a message board was asking about a feat to let characters wield improvised weapons. Here you go.
You have a talent for using nearby objects as deadly weapons.
Prerequisites: Base attack +1, stunning fist OR proficiency with all simple and martial weapons.
Benefit: You can wield improvised weapons without suffering the usual -4 penalty to attacks. Effectively, you are considered proficient with improvised weapons. Furthermore, as a move action you can pick up an improvised weapon from any square into which you can make a melee attack, and you never provoke an attack of opportunity for drawing or picking up a weapon.
It’s balanced since improvised weapons are at best on a par with simple weapons or martial bludgeoning weapons. Why would anyone pay a feat to wield substandard weapons at a penalty? It needs extras to be mechanically worth really paying a feat for, rather than as a class extra.
One exception: I’ve been told that some splatbook or other has ruled that tables can be wielded as improvised two-handed 3d6 weapons. The idea of someone swinging around a magical shatterproof table on a full attack is so preposterous that I’m going to assume you don’t allow 3d6 two-handed weapons at no penalty.