Here's is a strange little game that has been proven to increase fluid intelligence - "the ability to reason and solve new problems, which is a crucial element of general intelligence." I honestly don't understand the difference between fluid and general intelligence, but "practicing this kind of task for about 20 minutes each day for 20 days significantly improves performance on a standard test of fluid intelligence." "And this improvement lasted for up to three months." If there are any psych majors here who what to explain what is going on and why this technique works, I'd be very interested. Here is the program's home page on Sourceforge.net. From there you can go to the download page as well as get more info on the program and the research behind it. The game is not at all self-explanatory so you will have to go through the tutorial (something I haven't done yet). I did see that there are a huge variety of game modes involving shape, position, images and various auditory clues. If anyone checks it out, please share your experiences here.