This was a test I came across recently, claims to have been developed by cognitive neuro-scientists. It measures cognition/intelligence on 3 counts a) attentiveness, b) memory, and c) processing speed. Try it, let me know what you think of it - I found it interesting as most cognitive function tests do a forced choice where you can manipulate the results, in a way. This one is less manipul-able.
Lumosity - iq_tests:index
And a chirpy bleating little test for fun: reaction time (turn the volume up and get ready on the mouse)! No cheating. Post your score with a screen-grab. (Edit: Sorry Kiddo, they're sheep not goats, but at least they bleat)