The current study on improving educational materials for math is wrapping up. Soon we will be distributing the $400 in Amazon gift certificates. As of yet, participation has been low and there are very few participants in the lottery, so your odds are good! Remember that higher quality improvements and more accurate ratings earn more entries in the lottery. Visit the experiment at the following link,
If you tried the link earlier and you had any trouble with it, please try again as there have been many revisions to the system.