Wonderworld's Peekaboo Ball, which we highlighted in our recent holiday gift guide, is one of our favorite recent toys for toddlers. Small wooden "heads" protrude from the ball like spikes from a cartoon land mine, in a rainbow of colors. When the ball rolls, the heads are pushed into the ball and gently and quietly emerge again when gravity calls. They can also be pressed into the ball by curious little hands, and drop in and out of the ball based on its position.
You can buy the Peekaboo Ball from Toys and Games Online. At $10, this cute 2" wooden ball is worth every penny.