Reports. I put a lot of work into them. I don't like to work on them, but I like the satisfaction of getting a grade back. Truly, those grades are earned. I personally prefer written ones; I can always change something.
I usually don't think beyond the concept of what has to be written or said for a report. However, in language arts, I had to write a 3+ page research paper about how technology aids a disability. (Each student had the chance to choose the disability of their choice.)
I learned so much from having to write about the disability I chose. (Tuberous Sclerosis Complex. I chose TSC because my parents' friend's daughter has it.) I went from knowing nothing about it to having to cut down what I needed to write.
That report was an eye opener for me.