Attention span is widely described as the amount of concentrated time one can spend on a task without becoming distracted. Most educators such as psychologists agree that the ability to focus attention on a task is crucial for the achievement of ones goals.
SpanTest is an app which lets you test your ability for sustained attention period without getting distracted and your average visual memory span while helping you get better at it, at the same time. This is a great brain training exercise which people of all ages will surely love.