This would certainly be usable resource to incorporate into Critical Thinking workshops. They provide a free 30 day trial download access to test-dive! You can also review various aspects of the offerings available and there are various packages, as well. The book list is excellent, also.
This Web site is designed for ease of use. And provides excellent readily pracicable techniques that promote brain-storming and critical thinking. I think my participants will find using this in groups will be engaging, useful and fun!