interventioncentral.org...it is rather difficult to navigate because they have so much information. To get to the readability check:
1. scroll down to where it says "Favorite Downloads"
2. Click on "Curriculum-Based Measurement Warehouse"
3. scroll down and on the left, click on "Reading Fluency Probes"
4. Click on "Create Custom Reading Probes"
5. Type 3 separate text excerpts, one at a time, into text box and take the average of the 3 for R. level