While I find stupid those keyboard/mouse-ruining, action videogames that teenagers play, Puzzle games help to keep your brain alert, perhaps even delaying aging related inability to concentrate. I like those at: http://www.funny-games.biz/puzzle-games.html Interesting, easy to play (I hate reading lenghty instructions), yet free.
buy a nintendo DS and get brain age , after you play it a few times you feel smarter lol ... seriously
Brain Age... Starcraft.... Deal or No Deal... Baccarat... and that Chaos Theory game with the exploding dots. Now can't wait for Starcraft II to come out.
Since now you got all excited... this one can't be beat! http://www.amazon.com/Activision-Ba..._1?ie=UTF8&s=videogames&qid=1204215734&sr=1-1 If you can't become a great trader after sitting thru 18 straight hours of this, you shouldn't be in this business!