Let me introduce you a new game - Elemental Wars.
It is tactical\logic fantasy game based on original magic system.
The game has following features:
-story-driven single player mode - mage's wars for dominance;
-unique spell system based on touch-screen spell-sign drawing and spell book page turning;
-really strong AI which makes battles challenging but always possible to win;
-nice looking graphics with impressive magical SFX;
-5 charismatical characters each with unique stats and improving spell book during game.
But the main feature is - Elemental Wars is a smart tactical-based game that really provides a good fitness for your brain. It is simple enough to learn and never too challenging though.
You may find the game or more information here: