I've got a couple of questions, the first is, if you've passed the Mensa stuff, is there any point to paying the yearly subscription fee? Do we have any Mensa bods on here?
Also is intelligence nature or nurture. Both my DC have their Dads features, his hair, his lack of interest anything academic, his lack of interest reading. There's little that says they're my children, apart from a certificate for 16 months of morning sickness. 
On holiday a few years back I had my books out giving them interesting facts. DD & DS were giggling, I asked what was funny, they said why do you have to be so boring.
When I was there age I read for enjoyment, still do, loved learning stuff, my parents weren't that academic so it was all off my own back, my other siblings weren't pushed like I wasn't, they scraped through school.
My latest trick is to read a book in front of them, to see if they see me reading and think, oh I'll grab a book. It's early days but all I've got so far is, what you reading for?
Do you think kids are either intelligent and interested, or they just want to mess about. I was reiterating interesting facts about where we were, history etc. They're at an age to appreciate it if they wanted too.
Both are average in ability, DS is in a lower set for maths. DD is middle sets for both maths & English. I cruised along in the top set with little effort, but never talk about it. I know it's silly but I was hoping they'd inherit something from me that was good.