cognitive fun!

I would suggest PASAT - it requires lots of focus. It has been suggested that doing lots of simple sums under time pressure is a good way of exercising the brain; I understand that this is the basis of Dr Kawashima's "brain age" products.

Even if PASAT doesn't improve your IQ, it will very definately improve your mental arithmetic - and that is a useful skill in itself. At least, much more useful than learning to memorise patterns of flashing squares!

In my opinion it is the ability to concentrate and attend that is being boosted - most definitely a worthwhile endeavour in this attention deficit high tech world. There is probably a correlation between the ability to concentrate in a variety of contexts and IQ. If attention is pluralistic then maybe different games are required. For an IQ boost simply choose a game that resembles typical IQ problems or demands similar metacognitive processes. Personally I like N back and PASAT. I like the speed element of PASAT which you don't get with N-back.

Regards

As Far as IQ booster, I can't give an authoritative answer beyond Dual N-Back since there have not been any studies that I know of on the other test and their relationship to improved IQ.

However, games in the memory section seem to be the most mentally taxing. I've found PASAT to require more focus (for me) than Dual N-Back. Picture N-back is useful you can work on remember "more" items. The Multi-Modal N-Back in the experiment section is a great adaptation to the Dual N-Back.

Item span is good too, but it seem less taxing. Either you remember or you don't

I would venture a guess and suggest the experimental spatial updating program. It is very challenging at 2 cells initially and develops eye tracking as well as divided attention and focus in the spatial memory realm.