Filter adult content

Hello, I have created a vocabulary term for "tags" and enabled free tagging. Now every piece of content may be tagged. One such tag is "adult", and as users may upload adult content items, I am looking for a way of offering users to filter out such content.

I'd love to have a selection box at the top of my page with a check box to filter on or off any adult content, and default it to on, so they never have to see it, and yet still have the notice that they can turn that filter off (ie-make it visible). But ANYTHING similar to this would work. Any ideas how I can do this?

Christian