What are fun games to play with a 9 month old?

Here are two games that one of my friends recommended. http://www.babycentre.co.uk/a1011599/9-month-old-baby-games-first-week She played both with her baby girl who loved both games. Especially for the second game, her baby girl always giggled and often looked very amused when she found the ball. My friend also played the game at home and uses some towels and blankets instead of the sandbox to hide the toys. But she loved bringing her daughter out for outdoor play for some exposure to nature.