Posit Science produces products that improves brain fitness. Most notably, the Brain Fitness program and the InSight product. Jewel Diver is a demo game from the Insight product that helps you keep track of multiple moving objects. You can find some of their brain teasers that focuses on memory attention and sound discrimination as linked.
Hear what Dr. Merzenich, co-founder of Posit Science, have to say about brain fitness.