This is a great question. This term, I announced in my classes that if any student wanted to be challenged more, I would be glad to assign that student an extra project or projects to do. I made clear that no one was obliged to volunteer for such a project, but that I would be glad to work with anyone who did volunteer. One of my best students did in fact volunteer, and I am now working with him. I have to say that this was a wise thing for him to do for several reasons:
1. I was quite impressed that he volunteered.
2. I know him well enough to know that he did this because he genuinely wants to learn.
3. This is the kind of thing I will not soon forget and will be sure to mention in future letters of recommendation.
4. This decision of his sets an excellent precedent for other motivated students.
5. He is now learning extra material that is actually helping him with his "regular" work.
6. This can only help his final over-all grade.