My background is cognitive science. There are a lot of interesting paradigms used in cognitive psychology to examine particular cognitive skills. You might find it a useful approach to have a look at the mechanisms of some of these paradigms to give you some inspiration for game mechanics. A good starting point is PEBL. This is a free battery of experimental cognitive task you can download and play around with on your computer. Hope this helps.
Thanks! But I don't understand for what this program it.. My english isn't very good, I found PEBL, and I'll download it ^-^
Research psychologists use programs like PEBL to conduct experiments. The different tasks/games contained in PEBL examine different cognitive skills. In my work I have recently been creating games using these tasks as a starting point. PEBL is not very user friendly but you should be able to get it working if you play around with it. I do not have PEBL my self at the moment as my computer died two weeks ago therefore I cannot talk you through the process of getting it to work, sorry.