In Statistics 110, Professor Joe Blitzstein provides students "strategic practice problems," arranged by topic which help then do the problem set. The idea for the strategic practice problems came from chess, where strategies are organized by topic. The problems are posted on the website along with the solutions. There are a few problems on every topic for the week, and many of the problems are similar to the homework problems.
Joe comments that students really like this aspect of the course as it provides targeted extra practice for those that want it. The strategic practice problems and many other aspects of Stat110 are available for free on iTunes U.
An example of the strategic practice problems is attached.