First, I decided to first look at the History Channel web page, http://www.historychannel.com. I like this site because there is a lot of cool multimedia sources and I personally like learning about the past. I clicked on the "This Day in History" link and by watching a short video clip learned that on April 11 1970 (today in history), NASA launched Apollo 13. A couple days after the launch, the crew had to return due to an explosion on board.
I remembered that NASA had a really good missions page at http://www.nasa.gov/missions/. I explored this page with students earlier in the year. They were learning about manned and unmanned space exploration. This is a difficult concept for some young people because NASA missions are not a much in the spot light as they once were back in the space race/cold war period. Even those awesome pics of MARS escaped notice by many teens.
The NASA missions page is a great place to explore past missions like Apollo 13, current missions like the the Voyager, Interstella Mission, and future missions of the International Space Station. I was amazed at all that NASA is up too on a day to day basis.
Here is a very nice photo collage of Apollo 13 crew and craft from the NASA mission page.