Yeah, sounds like an oxymoron to have such a thing as a fun IQ test. But the test at lumosity is actually pretty fun. It's mostly visual Flash-based games, and the games are fun.

They claim that playing the games on their site will sharpen your mind, improve your memory, and increase your speed of thinking. I have no idea if they really do all that. But if the boss asks... that's why I am playing these addictive games.