"Unexpected Likes" and "Unexpected Dislikes" on "About your ratings" page.
On the "About your ratings page", it would be great to have sections that show which of one's ratings have the largest positive/negative discrepancy with the (leave-one-out) predicted rating for that movie.
To put it another way, it would be great to be able to see one's own eccentricities with respect to the algorithm as well as with respect to the bulk of MovieLens users.
That is an excellent idea! I think it could work especially well once implemented the "Recommendation Explanation" idea. This way the user will be able to figure out what went wrong about that particular prediction.