Remember Tamagotchi key chains? The pets that you would have to care for 24/7? Well there's a free iPhone app called Tamagotchi: 'Round the World that isn't as needy as the original Tamagotchi but it will play, eat, poop and even dance. It's actually a relaxing game with loveable characters that allows you to make the planet a cleaner and more beautiful place!
There's also a paid version with more features for $5.99.