Here's a simple and inexpensive little toddler activity that I made for my Mr. Three (who is almost two years old).
Pom Pom Size Sort
I recovered an empty frosting container with scrapbook paper then clear contact paper for my label and cut two holes in the frosting lid, one large and the other small. I then gave Mr. Three two sizes of pom poms to poke through the holes. (The holes will be smaller than the actual pom poms, but the smaller hole will only fit the smaller pom poms.)
He loves playing with this, and can open and close the can and sort independently. (Obviously, you need to closely observe any toddler when using small objects, like pom poms.) It is especially nice for my church bag, since it's a quiet activity. Even better? I made this all with items already on hand, so it was a free toy. Hooray for free!