It's going to be a busy summer...
I've just taken a look at The National Trust's 50 Things to do before you're 11 & 3/4s.
It's packed with inspiration to get muddy, closer to nature, and generally get out and about in our glorious great outdoors. The website lists loads of sensible, fun things to do, and most of them easy to achieve: go on a really long bike ride, climb a tree and build a den. Most can be done in London, including visiting a farm and playing with conkers.
Here's the full list - how many has your family ticked off?