Here's an iPhone app with a difference. Called Cool Tree, it enables you to plant a virtual sapling and nurture it into a tropical tree, like a sort of green Tamagotchi. Neglect it and you risk losing it to loggers and bulldozers!
Costing £1.79, £1 from the app is donated to the charity Cool Earth. The idea is that your purchase protects a real endangered rainforest tree in the Ashaninka region of the Peruvian Amazon which is, handily, geo-located for you to view on Google Maps as part of this application.
Three different species are available to choose from. Take care of your tree and you can unlock the next levels. You start with the Cocoa Tree but progress apparently to the more challenging Murumuru and Capirona trees.