One of my favorite mini lessons, or tricks to fill up time, is a good drawing game. I have several that take only paper and pen (or any thing that makes a mark) but this one always gets a good giggle from kids.
The object of the game is to draw a picture of something, without looking at your paper.
The trick it to have a few objects to draw. It can be from their own mind, a still life, or the person across the table. The first round, I’m pretty sure most kids are peeking 😉 and so Ive found its more fun to do 3 pictures on top of each other so that those perfectionist artist get past the ridiculous image they made. It also allows for another step to happen. After all 3 “pictures” are drawn, have them color in the shapes that have been created. If they use several colors, they can try to not have a color next to itself. This teaches positive and negative space and also gives them a fun challenge.
If they “mess up” remind them to use their creativity to “fix” it. I never let my students scribble out/tear up anything. There is always some creative or out of the box way to make it work 😀