If your 3.5 year old had been born 10 years ago, he would have still understood something about gravity at 3.5 with the help of Spaced Penguins. A simple Java o

If your 3.5 year old had been born 10 years ago, he would have still understood something about gravity at 3.5 with the help of Spaced Penguins. A simple Java or Flash game (can't recall which) about shooting a penguin into orbit around planets. This is neat, and good for Rovio but it's not anything more than neat.