Face it, if you're looking for sites that would run afoul of COPA, you don't have to look very hard. You can start with sites for ordinary political/social groups like NOW: The National Organization for Women, or the International Planned Parenthood Federation, or the American Civil Liberties Union. Sure, they're legitimate groups, but COPA says anything that might damage a child's mind is verboten, and on these sites, the little tykes might find damaging words like "breast-feeding," "semen," and "dissent." Can't have that.
As you know, great literature has often been viewed by the ignorant as a method for warping a kid's mind, so you can check out the American Library Association's Banned Book List for more information on the very best tools for the job.
Some say "dirty" words hurt kids. Some say the American legal system does so. Look at George Carlin's Seven Dirty Words in a court transcript and see how they can do so in tandem.
Yes, some sites ARE pretty gross, but that doesn't mean they shouldn't have Constitutional protection. They may even have their own bizarre charms. See what we mean at rotten dot com (a wonderfully offensive site) and Hell Hole: The web domain from hell.
You might think that a "Christian" site would be safe for kids, but you probably wouldn't think so after checking out The Truth About Hell. Supposedly they have actual audio of Hell. Do you want your tots listening to THAT?
Of course, just to prove that there's no such thing as a safe site for children, you may want to investigate the Teletubbies, featuring Jerry Falwell's worst nightmare, Tinky Winky. Is he gay? You decide...
Clicking on any of these links will open a new browser window for your viewing capabilities. When you have finished checking out the offending site, close the window and you should be safely returned to the COPA Cabana.