I've on occasion wanted to grade things like 'class participation' which is not an assignment per se. I've experimented with different approaches: make it an 'assignment' and hide it, or make it a grade item in the grade book without a corresponding assignment. Both have their problems. It seems like grading via an assignment has better ui - I can get an offline grading spreadsheet) than grading in the gradebook. On the other hand it seems odd to have to call "class participation" an assignment.
Can others weigh in with how to address this scenario? Thanks!