Just in case any of you have a 10+ child1 to buy for this Christmas, might I suggest the Haynes Build Your Own Internal Combustion Engine kit (picture here?)
I saw one in Borders after work today, and it's exactly the kind of thing I'd've loved when I was the age of the kid on the front of the box, so if you're stuck for a pressie for that child n your life who likes taking things apart, and your price range is around 25 quid...
1I'd just say "boy", but I don't want to degrade into gender stereotyping.
ETA: And yes, this means I've started my Christmas shopping. I won't be buying many pressies, as one Christmas present I want to give myself this year is a lack of panic and worry and last-minute angst and shopping in claustrophobic crowds...
I still love these kinds of things - but now I tend to buy them for other people and then offer to 'help'.