Research and write a document on what constitutes a "fun" user interface (especially designed for kids). The current interface feels "rigid" and isn't all that fun to use IMHO. For inspiration try looking up some of the design ideas used in Android. Highly subjective, but: list overscroll is fun, transitions are fun, bouncy stuff is fun (have a look at the effect used to animate boxes in the menu of Cut The Rope) etc.