It was on this date, July 29th, 1959, that Eisenhower officially signed into law the National Aeronautics and Space Act, creating NASA. Space.com has a good summary of the events that led up to that moment.
In honor of NASA's big day, I'd like to point out the new NASAimages.org site, a service of the internet archive, where you can easily search for just about any image NASA has ever taken. I've played with it a little, and I have to say the search engine is considerably better than other NASA image databases I've used. Try plugging in your favorite color, or your name (there were 86 hits on Sarah!), or your favorite moon, just to see what pops up.