Elevate

I need brain stimulation frequently. And I desperately need it when I am upset or feeling lethargic. And TV is not good. It dulls the brain further. Books may help me but it takes more time. If I am in a hurry and I need immediate mood lift, I can use some games - like word games or puzzles.

Peak :

 When I first downloaded it, I went all gaga over it. It had good UI, it gave me different set of games each day. There were different categories like languages, math and cognition. But by month end, I would use only word drop kind of game, and since it would not appear each day, I was upset and uninstalled it. But if you are willing to buy the premium version, it is good game for exercising your brain and feeling good about yourself.

Elevate :

 Well, I have downloaded it yesterday and I am still infatuated at it. The difference from Peak is, here the games appear to be more concrete. For example, you will listen to  a sentence - and the sentence does not appear on the screen, and answer questions based on the sentence. Or a set of words animate in high speed and then there are questions based on these. But one negative aspect is, it needs internet connectivity.

Lumosity 

This is also a good app. But I feel the user engagement is less, hence you will lose interest in it.

All the three games are available in android play and in ios too. Use them and go from :( to :) in a minute