Search the internet for uncommonly difficult IQ tesys and try out the hoeflin test. It is both a tough test and a nice puzzle. As for IQ itself, it is an excellent predictor of mental capacity and up to 130 scale, it predicts almost perfectly the educational level, profession and salary. Much higher levels (160 and above) are good indicators of genius but they may not encompass all of its aspects (think of the idiot savants). The internet pop-up IQ tests however......