Play the Pen Tool Game
This is a hidden gem by Adobe that you can access from the What's New pop-up box when you open Illustrator CC. or you can go to https://helpx.adobe.com/illustrator/tutorials.html to find it. It seems geared for little kids, but it helps with pen tool skills in a big way. Anyway, on the https://helpx.adobe.com/illustrator/tutorials.html page, click on Learn Essentials. Scroll down, and under the heading Create Artwork you will find Play the Pen Tool Game. I am using it is all my classes.