I'll be honest, this is the most random Advent Calendar I have ever come across. I mean I think eldest son would LOVE it. I am talking about the Haynes Build Your Own Radio Advent Calendar at Amazon. It's just £14.99 and is ideal for those older kids/adults.
The Haynes Build Your Own FM Radio Advent Calendar features 24 daily tasks and experiments to complete.
It doesn't require any soldering and isn't mega complex, so it's suitable for children aged 8 years old and above.
I like the fact, that this is rather educational as well fun and your child will be left with something they can actually use.
There's an instruction manual with it so your child will know what they are doing each day.
Delivery is FREE if you are an Amazon Prime member or are spending £20+. Otherwise, delivery is £3.99.