Brain Games - Boost memory power with free brain games
Next! Fitness - A.I. powered gym
Dualnback.works - Dual N-back is a specific brain training exercise, that's been shown by research - it might improve fluid intelligence.
LeveLisa - The brain game that creates creativity
PopcornTime iOS App - Watch movies & TV shows instantly on iOS (no jailbreak req.)
Hue Brain Games - Play interactive games with your Philips Hue lights