Here’s something different: how well do you think you can judge by eye? This game has you adjusting shapes and points, and compares your result to the actual result, and at the end, gives you a result based on an aggregate of your scores. I scored a 6.3 on my first try, and my worst individual attempt was 23 units off. Best individual attempt was 0.2 units off. Your scores in the comments.
[Link: The eyeballing game]