We got a splash pool for the back yard, largely so Ian and I don't die of sunstroke while Max plays in the yard. Max loves 'my water' and has lots of fun filling buckets and dumping them into the dump truck, using the hose and generally making a watery mess.
He wants us to get in the pool with him, but only through the 'door'. And you have to be prepared for a very adamant 'get OUT Daddy' when he's had enough and wants the whole pool back to himself.
So far, this thing is the best $9.99 I've spent on a toy!
