Since I am in the process of buying a home, I have been looking into homeowner rights. I found this story: a guy in Florida heard a scream in his garage and saw two cops arresting his wife. He proceeded to kick the shit out of them with their own taser gun and was later arrested for assaulting police. A judge aquitted him on all but one charge (you can't take a cop's weapon from him) because the cops had no right to be in the house (no warrant, no just cause). For the charge he WAS found guilty on, he was let off with time served (8 days).

Remember, your house is you castle.