The Miller Brewing Co. Age Check is a fantastic way to keep underage viewers out of the site. I especially love the ‘You Must be 21 years or older to enter this site’ above the entry boxes for your date of birth. The beauty is that this is to watch an ad that screens on free-to-air TV anyway.
You should also check out The Family Guide To Making Responsible Choices. If you do let me know what it says, I couldn’t get past the first line – ‘Dear Caring Parent’.