Peak is a mind-training game along the lines of Brain Training that lets you exercise different areas of your brain in order to improve different things such as concentration, self-control in tense situations, vocabulary, etc.
Users of Peak have to create a personal account before starting to play the different mini-games so that they can keep a complete log of all of their progress. Once you have a personal account, you can start training daily with all of the different tests that Peak offers, ranging from finding words in an alphabet soup to remembering patterns on a board.
When you finish any one of the tests you obtain a score. This score is logged on to your personal history, which allows you to see the progress you make in each one of the areas. This way, if you're drastically improving your vocabulary, but you don’t seem to make any advances in logic, you'll be able to see it.
Peak is an excellent app that combines the fun typical of videogames to the benefits of a health app. The difference is that Peak will help you keep a health brain instead of body.