I was poking around on the National Archives website yesterday and came across this interesting page. The archivists have posted high-quality scans of twenty of the most important documents in the collection, including the Declaration of Independence and the Articles of Confederation.
A few of the documents are a bit more interesting. My favorite is the cancelled check for the purchase of Alaska.
The Apollo 11 flight plan is also intriguing - I love the little cartoony spacecraft. So cute!