Here is a fun sorting activities for toddlers. Helps teach them their colors.
I went to AC Moore and bought these little cups that came with the covers you see above. They were $1 each (cup included with cover). I created a sorting activity with balls as you see below. Click Here to see how I created this. I didn't know what to do with the covers, so I created a separate sorting activity for those. All you have to do is follow the same steps in that link. All items were bought in the AC Moore wood section.
I recommend starting with 2-3 colors depending on the age. My son is 20 months old and all 6 colors were too much for him since it was his first time learning about color.