ReadTheory is a free site that lets teachers create virtual classrooms for students to read short passages and answer comprehension questions — teachers can then monitor their progress. It’s very simple to set-up classes.
It looks like it might have some potential, though I’m not thrilled that they require students to do a fairly lengthy assessment before they can move on to the readings.
I’m going to try it with my ELL students tomorrow. If you do the same with your students, let me know what you think.