Shake, Rattle and Roll
Wide mouth plastic containers, fillers, duct tape.
Toddlers are curious about sounds, so find a few plastic bottles with wide necks -- The Container Store is a good place to look. Then fill the containers with different objects like pasta, beans or pennies. Be sure to seal the container tightly; you may want to use some duct tape over the lid to be sure those small objects don't escape. Your toddler will have hours of fun examining what's inside, rolling the containers around on the floor and shaking them to hear what they sound like. To keep it fresh, just change the contents periodically.