What's a good promotion for weekdays?

No idea. What's your setup like? Do you have leagues?

Pick which ever day or days you want to improve, put a jar where everyone can see it, and throw 20 one dollar bills in it, when someone is going to break, inspect the rack to make sure it is tight and the eight ball is where it should be, collect a dollar from them, if they make the eight ball on a legal break they get the cash in the jar, if they don't the dollar goes in the jar. You can also keep a percentage if you like. You will need a bigger jar, because the pot will build quickly, it works because it is mostly luck, and anyone can win. A couple things to keep an eye on, is people putting the eight on the corners, loose racks, and don't let them just rack,and then re rack until they win, it is not fair to the others. Put a big sign in the window that says Break the Bank, anyone can win, or any catchy phrase, any questions, Pm me if you like.

Do something that gives you some advertising. People that have your bumper sticker on their car get 1/2 price pool on Wednesdays. People that wear your tee shirts get first drink free when playing pool. The shirts will get seen when they are doing daily errands and bumper stickers will be seen all the time during the week.