I used some pieces of yarn, ribbon, chenille stems bent into shapes, a googly eye, a jingle bell, a flower button, a bead, and some of our colored pasta.
I put it all in a small bottle and filled it with water, leaving about an inch empty at the top. I put hot glue around lip of the bottle and screwed the top on.
Actually, I'm not that thrilled with my first attempt. I put too many things in a bottle too small (the size is great for Little Lady's hands, though). The smaller snips of yarn came apart, which is fine, but all those small yellow threads seem to clog up the bottle. And, duh, the food coloring on the colored pasta soaked off into the water leaving the water a grayish color and the colored pasta a freakish, ghostly white.
I'll do better on my next try. In the meantime, Little Lady thinks it's interesting. At first she was pretty mad that she couldn't get the top off and proceeded to give me her mad rhino face, hand me the bottle, and walk off. Later, however, she sat down with a dancin' ring close by and played with the bottle. It is currently our changing table toy.
My cry for help: If you have any tips about making awesome discovery bottles, I'd love to hear them!