I want to create a forum in which only the instructor can launch a new discussion, but students (who wish to participate) have to respond to that discussion within a fixed time frame.
Let us say that I launch a discussion topic at 8 PM on August 13. I want to set a limit on all possible student responses (I can still post if I want after that time limit) at 11 AM on August 14.
Something like this would be very useful in allowing students to request regrades on exams / assignments, etc.