Jack says....

I was reading the computer today when Jack walked up next to me and said, "Can I bang the computer?" I, thinking he meant with his bare hand or a little toy, absently said, "Sure."  

Then I looked up. Just in time, as he had a HAMMER in his hands!

Redirected him to the couch to do his banging there.

Note to me: Always look at a kid before you agree to let them do something.