Tnxbai has IQ boost (iTunes Link) in the iTunes App Store for FREE for a limited time.

IQ boost is a brain game based on the only proven IQ boosting activity.

IQ boost is based on the Dual N Back exercise. The Dual N-Back task is the only mental activity that has been proven to improve your short-term memory and fluid intelligence.

IQ boost is very challenging and requires some dedication to get good at. However it is enjoyable and rewarding once you understand how to play.