Google's Doodle is about the 50th Anniversary of the 1st Human Spaceflight.
Here are some resources about this historic event, along with other resources about manned spaceflight:
NASA's Page on Yuri Gagarin - news article from the event, archived video, and summary of his flight.
Russian Archives Online - biography of Yuri Gagarin and history of his historic mission.
First Orbit - site tracks Gagarin's mission and includes transcripts of his communications with mission control. Includes a "video" of the mission as seen from the International Space Station, along with actual mission audio and news transcripts.
Today, 150 years ago, the Civil War began at Fort Sumter. Here are some resources about the US Civil War:
Civil War Traveler - this site has information about all of the historic sites from the Civil War that you can visit, with historic information and travel help. Great for learning about the Civil War and for planning a trip to historic places.
Internet Modern History Sourcebook from Fordham University - links, articles and historical documents
History Channel - interactive timeline, videos, links and more.
Social Studies for Kids - links, articles, and more - written kid-friendly
Using "Today in History" is a great way to talk about different topics and events with your students in any classroom.