Common Knowledge Quiz is structured so there's a 20-question test to complete each day (though, obviously you can actually do them as often as you like). As is common in these brain training things, the test results contribute to the intelligence rating on your profile. At the end of each daily test, you're therefore told if you're improving, which subjects you need to practice, and shown a line chart of your progress. Needless to say, you'll ideally want this line to be going upwards.
Count My Dokuyi Friends Count My Dokuyi Friends is a great mobile game for free, in which you will develop your logical thinking, and also have to do simple math, such as addition, subtraction, multiplication as well as division of variety of numbers
JewelsStar Your mission is to win Jewels Star, pass the levels and try to get all stars in each level
BattleShips Single or multiplayer Battleships game. The goal of the game is to find all the enemy's ships and sink them (more games on http://motoros.hu/games.wml)