Go to NASA's Kids Club to play all kinds of neat space games for elementary level kids. (I confess, some of the games are even fun for adults.)
You can also play, Space Shuttle Launch which provides math education as you need to solve a math problem to launch the rocket.
Another fun game (but not as educationally geared) is Rocket Robin where you need to get the launch parameters just right or your rocket explodes.
If you feel heroic, play Rocket Rescue. In this game you pilot a space ship that rescues fellow astronauts who are floating in space.
Also: Check out this blog entry by Joe Mendrzycki Apollo 11: 40 Years-One Giant Leap for some other excellent resources and additional links to the Apollo 11 story.
Catalog of Recommended Books, Games and Gadgets
Recommended Games and Gadgets