This video has been going around the interwebs for a while, so I'm sure the majority of you have seen it. I know there videos out there with the same general point, but this one is the best IMO-- no cheesy acting, no funny costumes, just two smart people telling you in no uncertain terms that talking to the police is generally (read: always) a bad idea.

http://www.washingtonceasefire.net/content/view/109/45/

Total runtime for both speakers combined is approximately 50 minutes. I recommend watching both of them all at once.