I came across this corpus while looking for corpora that are tagged for speech acts. I haven't had a chance to explore it too much yet, but it looks like it definitely has some potential pedagogical applications.
Not sure if someone's already posted this, but this is a great tool for getting an idea about text difficulty for reading. We regularly use this at the PIE for developing reading passages for Reading and Writing classes.
This looks like an interesting site for teaching students about a range of social issues. Complete lesson plans can be found and a variety of other resources related to "teaching tolerance" in the ESL classroom.