San Jose State University
San Jose State University: Categorical Fun
Six logical problems are defined to challenge students to use critical thinking skills as they tackle these brain-teasers. No answers are provided, but there are some instructions for how to approach the problems.
Indiana University
Indiana University: Science vs. Non Science
This mini-lesson at the Evolution and Nature of Science Institute site from Indiana University provides a criteria by which students can evaluate an idea or explanation for scientific credibility.