When you have found the right challenge, you often find yourself on the verge of your possibilities. Often you end up in a state called “flow”. That is the place where your capacities and your challenges meet each other. This state is very rewarding because you do something new, starting from a base you know and feel comfortable with. You can lose yourself in the game because of this. Your environment can get you into that state, but you yourself can get you there as well because of impulses you add to a game: new rules, other pieces of material, extra players, etc. A challenge doesn’t have to be “wow” or adventurous all the time. A small change to playing is often enough to give extra challenge.
Some examples: giving your Barbie dolls their first bath, kicking a ball into a tree, drawing the perfect apple, putting the handkerchief behind the animator, burying a shovel in the sand park, pranking someone, etc.