Trailblazing: Three and a Half Centuries of Royal Society Publishing is an interesting site presented in the form of a timeline of historic events and scientific articles. The articles are concise and cover some fascinating developments, for example a 1666 blood transfusion between two dogs, complete with sketches. As you can imagine this site is anything but dull! Along with the articles and images, there are links to further information.
The site is visually appealing and easy to use with the simple timeline, background images and colored circles representing different events.