We've been taking our daughter to Amsterdam since she was 8 or so. When we went last year she'd just "done" Anne Frank at school, so that was an obvious stop for her. What we've done in the past with a new city (for her) is let her do some research (internet, guide books) and let her come up with some things she wants to see. She doesn't mind museums, so things like the Amstelkring and the various art museums are Ok in small doses; the canal cruise is always a good choice, and the zoo is very good.
Last time, we went on a coach trip fro the afternoon, which went to The Hague and visited Madurodam, a kind of model village, with miniature landmarks from all over the Netherlands, which she loved.
I used to live there, and have been back several times since, so if you want ot sent me a private message with some details of what you & your boys are into, I should be able to make some suggestions.

Cheers
Iain

Hi nessywoo I too am from coventry and flew to amsterdam last march with my mum for mothers day. We didn't stay at night but there are lots of touristy things to do in the day so to take your kids should be fine. Canal cruise is excellent, although after the early flights out of coventry it can make you a bit sleepy.
Hope you have a great trip.
Surfer chick
x x x
P.s going back on the 12th March for hen weekend, so maybe have a different perspective of it then!!!!!!