Ok, I'm just posting because I see where people are coming from when they say rubrics are limiting, and I just realized why my perspective is so different...
It's great not to limit in the way that rubrics limit, but I think than in actual practice, all teachers do limit in these ways... the rubric just makes that transparent. I could never "guess" which things the teacher was going to mark for, and so I often got really bad marks for work that teachers at a higher level would have recognized with a higher mark. (Eg, a poem that I wrote in Grade 8 to be sent to a competition was failed by the teacher, but published as the first page of the competition anthology.)
Anyway, I think that if a student needs encouragement to go beyond the basics of an assignment, that's a separate issue from the question of "hitting the mark," which is what I would say rubrics are for. Maybe getting the student to come up with their own rubric for "I'll feel this project was useful to me if... very useful if... exciting if...." and then try to meet both standards at once.
My 14 yr old tutoree is so used to being bored in school that the hardest part of any project for her is to identify a way to make it useful to her. Once she ids what would make it "exciting," she's off to the races.
