Indeed, there are over 200 of them - I read most of them as a kid, at least all of the ones available in our local library.
http://www.kickstarter.com/projects/weiner/trial-of-the-clon...
http://www.kickstarter.com/projects/weiner/trial-of-the-clon...
Copyright only protects the actual content/expression of the work of the Choose Your Own Adventure, not the name of the series.
Stallman has a nice article about the conflation of the "intellectual property" laws here: https://www.gnu.org/philosophy/not-ipr.html