I was not an obedient student. I rebelled at assignments, declaiming against them as busy work and irrelevant. School didn't fit me, or so I thought. I learned early on to just change the assignments and do what I wanted, which usually got me praise for creativity, but it was unclear if I learned what I was "supposed" to. The first example I can remember occured in fourth grade with a particularly strict teacher who informed us squirming pupils that we were going to make Christmas tree stitchery for the holidays. (Stitchery was big at the time: yarn embroidery on burlap.) When I told the teacher I didn't want to make a tree because I didn't have a tree she ordered me to follow the assignment. I made a menorah instead. When she saw my completed work she gushed over it and wanted to keep it for an example. My nine-year-old self saw this as a mixed message.
As a teacher, I am reluctant to give assignments, both remembering how irritated I got and wanting to provide a comfortable environment to explore the artmaking process. I don't want to squish anybody's spirit. I agree it is hard to pull ideas out of the air sometimes, and more and more I've learned that people crave some kind of structure. When I teach my bookmaking classes I try to explain that the assignment is a framework, but work shouldn't be done to fulfill the assignment, work should be done to fulfill themselves.
One particular two-part assignment I like involves creating multiples of a folded book. Students make enough copies for everyone in the class (in our case, usually fifteen). This assignment provides a lesson on: design and planning; production and printmaking; experimentation with materials; and a forum to think about who the audience is for the book. After they complete this edition and exchange books, they are to pick one of their classmates' works and make a book in response to it, this time only three copies: one for them, one for the classmate whose book they responded to, and one for me.
When responding to a book, a few interesting things happen. I have seen students choose a book they admire so they can see how it was made. I have seen them choose a book with a topic or form they would never have chosen themselves, which pushes them outside their comfort zone. And I have seen how they get a new idea sparked by something they saw.
I've found that by working in this very focused way, the assignment encourages students to think about what they like and what they want for themselves after all.