Plastic easter eggs
Put the rice in the microwave for about 30 seconds. I've heard that this will kill off any little buggies that may be lurking. If the thought that there is a remote possibility of meal worms invading your craft project grosses you out, use some small beads instead. Scoop a little bit into the egg. Experiment with different amounts until you like the way it sounds when you close it and shake.
Smear a little glue on the rim of the egg and close it up
Now Paint! (We used some paint that was formulated especially for plastic, but any acrylic paint should probably work okay.)
Let dry, and you have a full basket of music-making, egg-shaking goodness!