A humble garden shed, painted and prettified to make a gorgeous playhouse for girly girls like my 5yo M. She would LOVE this - when she's too cool for a playhouse dad can paint green and park the lawnmower.
Many girls could juggle 2 or 3 balls at a time against a wall. Their complex games involved high speed bouncing moves and when that became too tame they would toss the ball between their legs or twirl around before catching the ball. All of this was accompanied by singing of various rhymes.
Yes, we live by the beach but the girls would still love this! Would convert into a seating area with cushions on top when not in use... And this is a fabulous site for contemporary ideas. Wish I lived in London so they could come and sort our garden out!