There is nothing you can do.

I've received several close variations of this email over the last few days:

Dear Professor,

I really wanted to get an A in your class.  I know the course is over, but is there anything that I can do to raise my grade?

What I want to reply is:

Dear Student,

No.

OR

Dear Student,

I really wanted you to get an A in my class, too.  If only you had turned in all of your work throughout the semester in a timely manner, that might have happened!

What I really write is:

Dear Student,

I do understand your desire to receive an A in my course.  However, the semester has finished, and there are no additional extra-credit activities or assignments to be completed beyond those that were offered throughout the 16 weeks of the course.  I do hope that although you did not receive the grade that you hoped for, you enjoyed the course, and that you have a restful break.

If only students were as eager to do work throughout the semester as they are when the semester is finished and there is no work to do. 

"Guns have been an issue since before time."

You guessed it - I am grading essays.

Dear Professor...

If I sent the same kind of emails to my students that they send to me, they might sound like this:

Dear Students - I have to cancel class today because I left my briefcase in my cousin's car and she had to drive my aunt to San Francisco for a doctor's appointment and they got in a car accident and the car is totaled so I have to get a whole new briefcase and also my computer was damaged and I need to get that fixed and I won't be able to do that until tomorrow.  Thank you for understanding.

Dear Students - I have to cancel class today because I woke up early this morning not feeling good and don't know if it is the flu or that I am just nervous about today's lecture, but I cannot be sick because the holidays are coming and I am traveling so I cannot come to class.  Thank you for understanding.

Dear Students - I have to cancel class today because I decided to change the subject of today's lecture but had a hard time finding information on the new topic so the lecture is not ready and I hope that you are ok if I give the lecture to you a little late. Thank you for understanding.

Such nonsense.  Happily the semester is almost over.