Are there any good "brain training" applications online?

Here is my favorite:

http://chess.emrald.net/

It trains the brain to think faster , and you have your history and progress

I don't know of any prepared set of brain games, but if you want to make a real brain training games you should change the rules of the game every couple of days and have all kind of games - memory, strategy et cetera.

Otherwise the brain will know what to do next in the game instead of looking for a new way in a new game.

Here are some sites with brain training games:
http://www.entheosweb.com/flash_games/puzzle_game.asp
http://games.download3000.com/play/square
http://www.buzzle.com/games/MetroMatch.asp

Some comments to your answr:

1. The first link is not online , you can just DL the games.

2. The second link is online , but only for 4 times. I do not believe that it does anything good for your brain - did you try to play with those bubbles? After 4 times you have to register..

3. The third link is just a memory game. You do not have to force your mind on any subject.

Please try the chess link - it gradually fits your own level (if you just have a bsic knowledge) and it is sofisticated in its ability to @punish@ you by making harder challenges if you do it correctly and easier one if you fail.

I didn't proposed a prepared set of brain games, I wrote that if he wants to make a set on his own, he should have all kind of games - including a simple memory game that exercises your mind...

The purpose was not to play these spesific games, but to show types of games that exercise your brain in different ways.