Incredibox is a wee interactive thingy which lets you make music with different effects. You get to play with sound effects, voices and all manner of twiddly bits such as beat box, percussion and chorus. The info on the site says that you will discover the magical universe of ‘The incredible Polo’, be that as it may, it is very cute for a while. Play it next to a teenage boy and you are likely to have harm done to you (or to your laptop).
Here is the website