Sphero is a smart ball. Orbotix, the company behind this piece of technology calls it a "robot ball" and "a game system". Either way it's a an interesting kit, with limitless possibilities.Basically Sphero is a robot you can control from your smartphone or tablet. From those devices you establish a Bluetooth connection to your Sphero and can play interactive games, race against friends and even program it yourself by either using the SDK or using one of many apps that alllow you to create routines that will keep it busy for a while.

Sphero is water proof as well so you can take it to the pool and exercise trying to catch it - or just have some fun play. It is also pet friendly as in it won't break in normal play with your cat or dog. I did see the excitment a dog feels when this noisy little ball starts rolling around the lounge - our small dog lounged, barked, growled, ran away and otherwise seemed to have fun every time I had Sphero on the ground.
It does take a bit of practice using the Sphero app to get to a point where you are comfortable controlling Sphero. It is only a few minutes though and you will feel that "driving" it is not as hard as it seems.

The apps can control many different aspects of the robot, from positioning, movement and colours while gathering information from its sensors. This is used by many apps to provide a bridge between real physics and virtual game environments. Some games are simple - one of them is basically a "catch Sphero when the right colour is showing". This would be easy if not for the fact the ball will be constantly shaking and changing colours at increasing speed. Other games will mix elements of real world (captured via camera) creating a race course you have to navigate through using your device to control the robot.

A third type of apps are the development ones, such as MacroLab. With MacroLab you can arrange commands and settings in any combination you choose to let Sphero drive autonomously, follow unique patterns, and more. These apps offer a good introduction to procedural thinking and basic programming skills.
Sphero is battery-operated and recharging is pretty easy: drop the device on its cradle and it will recharge thanks to inductive charging (similar to how some electric toothbrush charge systems work). It takes a couple of hours to get it fully charged but I didn't get to the point where running out of charge would spoil the fun.

Here is the promo video for this toy|robot|game system|development ball:
Sphero seems to be more than a "robot ball" and "game system". It can be a great introduction to development for kids and a platform to introduce real life interaction concepts to existing developers. As such it is a great educational tool.