So we always take the day of our LO's birthday off and go do something fun as a family that they would like.

My family will (95% sure) be up here visiting this year as well to celebrate.

Any ideas for something that will be fun for a 4yo but won't bore 12 yos to death? I'm leaning towards a indoor water park...it will be end of April in the NE. So still chilly!

Thanks!