Summer clubs for kids

We are looking for suggestions for things to do with two children over summer that are 10 and 12 years old that are whole days rather than a couple of hours and don't need to sell a kidney to afford!

Last year we did the YMCA which was pretty poor.

We also trying jumping passes at the trampoline parks but after a few visits they got bored and it was only a few hours.

Any and all suggestions welcome!