This is not the weapon that was used in this particular case.  But this is first thing that comes to mind when I hear souvenir baseball bat.  You know, one of those thin wooden bats that usually goes around 18 inches in length.

I never thought that one could be used in a fit a fury, but according to a Lufkin Police report, apparently it can.

Just after midnight Saturday, 54 year old Dorothy Brown was arrested and charged with assault for hitting her boyfriend with a souvenir baseball bat.  I don't believe the man was too badly injured.

Once again, I'm just assuming that a bat like in the picture was the weapon of choice.  It probably wasn't an Astros souvenir bat, otherwise she would have swung and missed.