My mom made A this awesome color sorting strip last year from fabric scraps.
A doesn't stick with the activity for very long, but he does pull it out frequently.
We've gathered a collection of small items (I think my mom and sister started with sets of things from the dollar store that came in a variety of colors like hair bands and clips, toy cars, and foam shapes. We've added blocks, pom poms, and other random things.
Obviously the idea is to pick an object from the box and sort it onto the right color square. A confidently knows all of his colors except black/brown and pink/purple which he still gets mixed up.
I threw in a pair of tongs to make things a bit more interesting for him.