PianoBall - Fun With Learning ($2.99) by 4baam provides not just musical fun, but mesmerizing colors and educational tid bits for little ones. It's like the coolest toy piano your kids will ever come in contact with.
PianoBall impressed me with its graphics from the very first second. My kids were clamoring to get my iPhone in their hands as soon as they saw me open it. I wondered if it would be all looks and no substance, but thankfully it delivered musically and educationally as well.
There are many modes of play to choose from. They include: instrument mode, color mode (learning colors), rainbow mode (just for fun), keyboard mode (one octave of keys), learning tunes, and magic (fun with stars). This keeps the fun going for quite a while.
One feature the developers were very smart to include was the "lock" feature. This allows parents to be a bit "sneaky" and lock the mode they want their child to focus on for a bit. This is also great for little ones with clumsy fingers who accidentally press wrong buttons and get frustrated by always ending up back at the main menu.
I appreciate that PianoBall includes tune-learning mode (guided playing) and keyboard mode for kids who are just learning to play tunes. I would like to see the developer add a mode where the keys feature letters on each key depicting which note that key represents. This would be great for teaching kids a piano scale.
If you want your child to eventually learn music and want their first impressions to be fun and whimsical, PianoBall will be a great tool for you. My kids love it, and I venture to say yours will as well.